Hello all,
I have a 2003 Jeep Grand Cherokee with 135K miles. Within the last 1,000 miles the car has lost about 1 & 1/4 mile per gallon in the last 1000 miles and has started to stall when just started and had to have the engine reveved to keep running after started. I have checked the plugs and they are OK, I changed the oil 2 days ago and put in a brand new battery last week. The jeep diy work manual that I have only has how to change oil filters for models from 1993 to 1996. No mention of later models (all other things in the manual are specified by year of auto). Any suggestions of what to check next?
The first step is to have the OBD system scanned for stored trouble codes. Hopefully, some codes have been stored. Without trouble codes, you will just wind up “throwing parts” at the problem.
Not putting out a few bucks (< $20) for a current repair manual could cost you many more dollars in wrong work being done, and wrong parts being changed.
The repair manual will tell you if the fuel filter is in the gas tank, or not.
A new fuel filter, and new spark plugs, may be all that’s needed. Problems like those on your vehicle aren’t often only one item.
Most of the time a vehicle stalls at stops is because of a dirty throttle body.
Take the intake hose off, open the butterfly valve and spray some carb cleaner inside. You might need a small brush to help.
Take “Hellokit’s” advice and change the fuel filter. A clogged fuel filter won’t allow the fuel to atomize and that will cause lower fuel mileage, plus the head pressure on the fuel pump will prematurely wear it out.
And of course, Ethanol will cause a drop in miles per gallon also.
What ever you do don’t just start throwing parts at it hoping for the best.
Check the maintainance records, clean the throttle body, & change the fuel filter.
You might have to scan for codes. I think it might be done at a Advanced Auto,
call to verify. Sometimes, its $75.00. A KOER (key on engine running) test might be in order. Start with the cheap fixes first, which usually is maintainance.
Good luck
Caballero