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2011 Jeep Grand Cherokee - Poor performance after service

My 2011 Jeep Grand Cherokee Limited is performing poorly after a major Maintenance 3/19 the MPG went from 19 ad 20 city driving to as low as 14.5mpg. Maintenance performed was: 1) Repl Air filte, 2)Throttle body Serv, 3)Fuel Injector Serv, 4) Brk fluid Exchf and Trans flush at 57892 miles. Expecting to improve or keep mpg - something went terrible wrong. The dealer has checked twice by now and can’t find what went wrong and was told I have to live with a4 to 15mpg. I can’t and wont accept that, would you have an idea what could it be?. Now there is a recall for a Fuel Pump Relay but the kits have not arrived to replace it. In the mean time I have dealt with this problem for a 1 year no. Please help me, I love my car but can’t maintain the poor level of performance.

The fuel economy rating for the Grand Cherokee is 14 or 16 MPG depending on powertrain, if your display was showing 20 MPG that may have included a lot of prior highway driving or a problem with the display.


Fuel relay wont fix anything . That is for a no start condition . If you had all that stuff done and it really doesn’t need to be done at 50K miles then maybe they fouled the plugs .

I may try that, although I was told that plugs did not need replacing. My mpg was actually 19 to 21mpg but it deteriorate immediately after this particular maintenance. I know the poor performance because I replacing the gas for less mileage trips than before and similar gas is burning and the engine does not feel sluggish or having difficulty pulling. It’s is a mystery - I’m also in contact directly with Jeep in Detroit.

Thanks for the suggestion.

R. Fletcher

Were you tracking the mpg using an onboard computer or by actually recording the odometer reading and fuel consumption at each fill-up? Just because the dashboard says 19-21 mpg doesn’t mean that’s actually what you’re getting.

Otherwise, I’d also consider if environmental factors are at play. Did it get much colder in your area around the time of the service? Colder temps would lower your fuel economy, and make it seem like it was related to the service.

I actually keep a record of the trip mileage every time I fill up the thank, and have done this for every single year I’ve owned this SUV, I know what I’m talking about mpg VS miles traveled. I fill only full tank not a little here and there. As you said I actually keep a record of the odometer reading and fuel consumption at each fill-up. So far I’ve not heard anything that will actually help me.



The sticker estimates 16/23 for city and highway driving. You said as low as 14.5, that is meaningless. What is the average since you had the maintenance done?

Well here’s one thing that will help you: don’t post your email address on a public forum, unless you want to be completely inundated with spam.

What about my second question: can you think carefully if there were any recent weather changes or other external factors coincident to the service that could be responsible for the lower mpg?

No, absolutely no changes on weather than the usual, and you’re right got a lot of no helpful tips or questioning like, i don’tknow what I’m talking about. Thanks for your interest though. The mpg has actually improved by 2mpg from 14 to 16.5.

R. Fletcher


and the weather is warming up, they also might be bringing the summer blend of gasoline back. Another thought I have is tire pressure. Under-inflated tires have poor mileage

It is not really a good idea to put your email on an open forum web site . And I don’t see any comments that should upset you .

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