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We just wrapped up a 650 mile road trip leg through the flat mid-west in our 2018 gas Limited, and only averaged 22mpg with no traffic and 100% flat open highway. ACC was set at 80 (75mph limit). At 80, it’s sitting right at 2250 RPM, which means it’s not shifting above 7th gear.

I really expected better MPG out of this thing. Around town, we only get ~12mpg.

I’ve seen some posts from others where they are getting 28-30mpg. What gives? I know the speed hurts mpg some, but why won’t it upshift past 7th gear?

Is there a TSB’s/Recalls that might explain the poor performance?
 

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There are dozens of things that can affect fuel economy, and these vans will almost never see ninth gear.

I noticed mine stays in seventh most of the time when I'm above 65 mph, and 8th between 55– 65 mph. Wind resistance increases faster than velocity, so there's a point where the engine needs more torque than can be throughput in eighth gear which necessitates the downshift to seventh.

This is the most fuel-efficient van I've ever owned, and I routinely see 26 – 28 on the highway at 75 mph. It's never that high in the cold, weather though, and wind direction and velocity also play a big role. I wish we had more control and visibility of the transmission gear selection, but having that many ratios allows the PCM to pick the most efficient ratio possible. It seems to be a bit conservative on the upshift to limit gear hunting, which is probably a good idea for longevity of the transmission.

Remembering you’re driving a 5000-pound box with more interior volume then a Suburban at 80 mph. It’s not a Prius.
 

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I’m not expecting Prius mpg, but you are getting 6mpg better than mine. That seems like more than noise. Yours also sounds like it shifts into 8th. As far as I can tell, mine never has.
 

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I’m not expecting Prius mpg, but you are getting 6mpg better than mine. That seems like more than noise. Yours also sounds like it shifts into 8th. As far as I can tell, mine never has.
I don't know about that… Mine will only will do that well in the summer with warm weather.

I have no way of knowing where you're located, but I'm in Minnesota. I haven't seen that kind of mileage since August or September. In the cold weather I might see 25 MPG at 60 mph, no way it would do that well at 80. I don't drive that fast, so I really can't test it out for you. Mine would not be in eighth at 80 unless I’m coasting down a long hill.
 

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.....I noticed mine stays in seventh most of the time when I'm above 65 mph, and 8th between 55– 65 mph. Wind resistance increases faster than velocity, so there's a point where the engine needs more torque than can be throughput in eighth gear which necessitates the downshift to seventh....
I sure would like to know how you determine what gear your Pacifica is in. Is there something on the display screen that I have not found yet that tells you?
 

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I sure would like to know how you determine what gear your Pacifica is in. Is there something on the display screen that I have not found yet that tells you?
I wish it was that easy!

Unfortunately Chrysler didn't see fit to provide us with that information, so the tachometer and wheel speed to infer transmission gear. I have the spreadsheet saved in my Dropbox that I downloaded from another member on here, take a look: https://www.dropbox.com/s/lvcxikn8czs7vo5/Pacifica_Gears_vs_Speed.xlsx?dl=0
 

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That is one slick chart.
Thanks.
 

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My 6/18 build date Touring Plus will run in 8th gear up to 68 mph if not on cruise control. Just got back to western Illinois yesterday from Grand Prairie, Texas. Didn't use cruise. Ran a lot of 63 - 66 mph. Fought northwest winds. Trip computer showed 31.0 mpg as I pulled into my hometown. If I had used cruise control, it would have de-selected 8th gear, run in 7th, and gotten 1 or 2 mpg less. That is disappointing. Just bought the van in November. I'd like it to run in 8th on cruise, but the slightest rise will cause it to shift to 7th and stay there.

As far as speed, wind resistance goes up by the square of the speed increase. 80 mph is 14.29% faster than 70, and wind resistance at 80 is 30.6% higher. 80 mph vs. 65 is 23.1% faster with 51.5% more wind resistance. Get on a bicycle and try riding fast. You will get the picture very quickly.

The Pacifica's coefficient of drag is only .30 when equipped with the under-pan. (Meaning it has 30% of the wind resistance of a block of the same frontal area going through the air.) That's respectable. By comparison, the 1996 Dodge Viper R/T has a cd of .45. Wikipedia has an informative article on automobile drag coefficient that is worth reading.
 

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My 6/18 build date Touring Plus will run in 8th gear up to 68 mph if not on cruise control. Just got back to western Illinois yesterday from Grand Prairie, Texas. Didn't use cruise. Ran a lot of 63 - 66 mph. Fought northwest winds. Trip computer showed 31.0 mpg as I pulled into my hometown. If I had used cruise control, it would have de-selected 8th gear, run in 7th, and gotten 1 or 2 mpg less. That is disappointing. Just bought the van in November. I'd like it to run in 8th on cruise, but the slightest rise will cause it to shift to 7th and stay there.

As far as speed, wind resistance goes up by the square of the speed increase. 80 mph is 14.29% faster than 70, and wind resistance at 80 is 30.6% higher. 80 mph vs. 65 is 23.1% faster with 51.5% more wind resistance. Get on a bicycle and try riding fast. You will get the picture very quickly.

The Pacifica's coefficient of drag is only .30 when equipped with the under-pan. (Meaning it has 30% of the wind resistance of a block of the same frontal area going through the air.) That's respectable. By comparison, the 1996 Dodge Viper R/T has a cd of .45. Wikipedia has an informative article on automobile drag coefficient that is worth reading.
I achieved the same MPG driving from Texas up through the Midwest this past summer. The lower speed limits and lack of hills allow for very good fool economy.

My theory on the 7th gear/8th gear thing: I guess the transmission software has hysteresis built in to limit the frequency of 7th/8th shifts on the highway. Any substantial throttle movement restarts the hysteresis time window. The cruise on this thing is programmed to use very aggressive throttle inputs in an attempt to maintain the exact set speed. So it exceeds the limit, rests the time window, and almost always stays in 7th gear. I see this same operation on very flat stretches of highway - for example I-10 west of Houston. It will occasionally go into 8th gear, but not nearly as much as if I operate the throttle the old fashioned way.

I bet you can thank consumer workshops for this behavior. I think they express a preference for robotic exactness of the set speed over smoothness and efficiency. They also express a preference for touchy throttle control, where the car leaps off the line but is difficult to drive smoothly.
 

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Many good comments on wind impacting mileage and speed control being more for maintaining speed than for economy.
2 other factors I didn't see mentioned - How laden were you? More passengers/gear, poorer mileage.
Tire pressure is another huge factor - Keep them inflated for best mileage.
 

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12 mpg around town? Wow. My wife drives our 2018 Touring Plus exclusively on city streets (it only sees the highway 1-2 times per week when I drive it on weekends) and the average has been holding at 19 mpg since we bought it. I rented a 2017 Pacifica Limited during a trip to southwest Virginia in September and averaged 17 or 18 mpg while driving on nothing but mountain roads the entire time. I was, however, completely unimpressed with the transmission in those conditions. It would constantly hunt for gears and it was a real challenge trying to maintain any sort of speed on the mountain roads.
 

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I don't know about that… Mine will only will do that well in the summer with warm weather.

I have no way of knowing where you're located, but I'm in Minnesota. I haven't seen that kind of mileage since August or September. In the cold weather I might see 25 MPG at 60 mph, no way it would do that well at 80. I don't drive that fast, so I really can't test it out for you. Mine would not be in eighth at 80 unless I’m coasting down a long hill.
I'm in MN also. We had a trip over Christmas where we didn't get much better than 23-24, where in the summer we usually get up to 27-28 on trips. One time we got almost 30 on a return leg. I was seeing 9th gear every now and again during spring and summer, i know this as rpms would drop to about 1500 at 75 mph. I've still been seeing it do 8th quite a bit. But its been months since we've seen 9th.

Winter affect FE huge, and apart from cold temps, the fuel is blended for winter here and it affects FE on winter blend also.
 

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I sure would like to know how you determine what gear your Pacifica is in. Is there something on the display screen that I have not found yet that tells you?
Apparently there are HUD (Head's Up Display) units that will display that type of information. Search the threads. They plug into the OBD port.. As with all items that attach there, the general wisdom on the threads are to unplug it before getting dealer service. I think most are passive(i.e. they only receive information.) Personally, other than the dongles that kill STOP/START, I would stay clear of any active plug-ins.
 

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I don't know about what gear but I know that I am consistently below 2000 rpm when cruising on the freeway with ACC on. I recently took a 1000 mile round trip with the majority being on the freeway 70 mph or 65 mph depending the speed limit and averaged 30.1 mpg for the trip.
I am very pleased with my mileage from my Pacifica.
John
 

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We got our 2017 Limited Gas in September (used). I have two significant data points to throw out:

Wife driving the kids to school in heavy city traffic every day gets 16 MPG.
On a road trip to AZ, set cruise control to 79 MPH and I got 25.6 MPG. That was with 3 kids and all our crap in the van, I thought that this was decent but I suspect this van can do better with an updated shifting/cruise control setup.

Also, PSA I didn't see mentioned above... If you under-inflate the tires a few pounds it can have a significant negative impact on fuel economy. I slightly overinflated all 4 tires to 38 psi before our road trip.
 

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Discussion Starter #17
The return trip showed largely the same behavior in terms of transmission gear, never getting above 7th while at cruise. MPG was, however, significantly better than the trip west. Once out of the mountains, with ACC set to 80, we were seeing 27.5mpg on the flats for several hundred miles, with long stretches of no wind in the low 30’s.

I’m wondering if the trip out had some major headwinds, or if fuel quality played some significant role (I filled up at a station we don’t usually fill up at). Air temps were below freezing for most of the trip home, cooler than the drive out. The first ~75 miles of the trip were in negatives, with a min temp of -14F.

Still, the trans never hit 9th gear so I’m still baffled at why there is a 9-speed at all. It did shift into 8th for a very brief stretch coming out of the mountain passes, but otherwise it was in 7th for the majority of the trip.

Maybe I’m underestimating just how tall 9th is, and how bad the aero is on the van. I’ve never had a car that didn’t make enough power to cruise in top gear.
 

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The cruise on this thing is programmed to use very aggressive throttle inputs in an attempt to maintain the exact set speed. So it exceeds the limit, rests the time window, and almost always stays in 7th gear. I see this same operation on very flat stretches of highway - for example I-10 west of Houston. It will occasionally go into 8th gear, but not nearly as much as if I operate the throttle the old fashioned way.

I bet you can thank consumer workshops for this behavior. I think they express a preference for robotic exactness of the set speed over smoothness and efficiency. They also express a preference for touchy throttle control, where the car leaps off the line but is difficult to drive smoothly.
Not a Pacifica owner yet; driving a DGC with 6 spd automatic, but the behavior is similar except that it will eventually shift back up. I far prefer the old style cruise control that was controlled by engine vacuum and throttle position because it would allow speed to drop off 5 mph or even more before forcing a downshift (or going back further in automotive time, not even causing a downshift). These later ones downshift at the drop of a hat, like 2 mph, and that kills fuel mileage when the rpm's jump up and don't come back down for an extended time. I find myself driving without cruise on hilly interstates so that I can back off the throttle a tad to prevent a downshift on a grade that doesn't really require a lower gear. So I lose 5 mph for a bit--no big deal. I gain a couple of mpg on some roads I routinely travel. Tiring to drive without cruise, which I'd prefer to use, but the sudden acceleration to gain back a couple of mph (and often go past the target speed before backing off) is annoying and costly in terms of fuel usage. I don't care what consumer preference groups indicate, I have no need to hold my speed within 1-2 mph unless I'm dealing with a tailgater. Too bad we can't have manual control of gears. I think I'm smart enough to avoid lugging the engine by staying in too high a gear when I shouldn't.
 

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We just wrapped up a 650 mile road trip leg through the flat mid-west in our 2018 gas Limited, and only averaged 22mpg with no traffic and 100% flat open highway. ACC was set at 80 (75mph limit). At 80, it’s sitting right at 2250 RPM, which means it’s not shifting above 7th gear.

I really expected better MPG out of this thing. Around town, we only get ~12mpg.

I’ve seen some posts from others where they are getting 28-30mpg. What gives? I know the speed hurts mpg some, but why won’t it upshift past 7th gear?

Is there a TSB’s/Recalls that might explain the poor performance?
Since wind resistance increases as the square of the speed you would expect a decrease of about 30% in fuel mileage going from 70 mph to 80 mph if all the frictional drag is due to air resistance. If your mileage is 30 mpg at 70 mph that would be a drop of 7mpg. If we assume that wind resistance is actually 3/4 of the drag on the car at this speed, the actual fuel mileage drop would be about 5 mpg.

However, since the power needed to overcome this extra drag has a time factor to it (for instance even without an increase in wind resistance going twice as fast needs twice the power since the distance covered is in half the time) the total power required increases as the cube of the speed. For example a vehicle that needs 40 horsepower to go 70 mph would require 60 horsepower to go 80 mph. In order to supply this extra horsepower a vehicle’s engine has to rev higher at the higher speed which would require a lower gear if it was already turning at maximum efficiency at the lower speed. Thus the extra gear ratios in the newer transmissions help fuel mileage more at moderate speeds. Thus it would not be surprising to see a drop of 6 or 7 mpg traveling at 80 mph rather than 70 mph due to increased wind resistance and lowered engine efficiency necessary to meet the power requirement.

This is what I have experienced on my van.
 

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The return trip showed largely the same behavior in terms of transmission gear, never getting above 7th while at cruise. MPG was, however, significantly better than the trip west. Once out of the mountains, with ACC set to 80, we were seeing 27.5mpg on the flats for several hundred miles, with long stretches of no wind in the low 30’s.

I’m wondering if the trip out had some major headwinds, or if fuel quality played some significant role (I filled up at a station we don’t usually fill up at). Air temps were below freezing for most of the trip home, cooler than the drive out. The first ~75 miles of the trip were in negatives, with a min temp of -14F.

Still, the trans never hit 9th gear so I’m still baffled at why there is a 9-speed at all. It did shift into 8th for a very brief stretch coming out of the mountain passes, but otherwise it was in 7th for the majority of the trip.

Maybe I’m underestimating just how tall 9th is, and how bad the aero is on the van. I’ve never had a car that didn’t make enough power to cruise in top gear.
Your return mpg seems quite decent given the speed and weather conditions. On a 300 mile drive I make regularly I have seen from 24 to 31 depending on wind, weather, etc. All driven at about the same speed.

Ninth gear gives 1300 RPM at 70mph. I’ve seen it a few times, always on long, gradual downhills. My guess is the engine can’t produce enough power in most driving situations at that rpm, or perhaps it’s more efficient to produce the required power level at slightly higher rpm.

The transmission was design and and built by a third party (ZF) then sold to various manufacturers (Chrysler, Honda, Land Rover). So it isn’t specifically designed for the Pacifica. That said, it is used in the Odyssey as well. I lurk about that forum, but haven’t seen any discussion of when, or if, it uses ninth gear.

Not a Pacifica owner yet; driving a DGC with 6 spd automatic, but the behavior is similar except that it will eventually shift back up. I far prefer the old style cruise control that was controlled by engine vacuum and throttle position because it would allow speed to drop off 5 mph or even more before forcing a downshift (or going back further in automotive time, not even causing a downshift). These later ones downshift at the drop of a hat, like 2 mph, and that kills fuel mileage when the rpm's jump up and don't come back down for an extended time. I find myself driving without cruise on hilly interstates so that I can back off the throttle a tad to prevent a downshift on a grade that doesn't really require a lower gear. So I lose 5 mph for a bit--no big deal. I gain a couple of mpg on some roads I routinely travel. Tiring to drive without cruise, which I'd prefer to use, but the sudden acceleration to gain back a couple of mph (and often go past the target speed before backing off) is annoying and costly in terms of fuel usage. I don't care what consumer preference groups indicate, I have no need to hold my speed within 1-2 mph unless I'm dealing with a tailgater. Too bad we can't have manual control of gears. I think I'm smart enough to avoid lugging the engine by staying in too high a gear when I shouldn't.
I agree, I would be fine if the cruise was a bit more relaxed and gave up a few mph while climbing in exchange for more moderate driving behavior. It is better than my last van (‘08 Honda) which would lose 5mph, then downshift and accelerate up the hill!
Talk about way to burn fuel!
 
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