97 jeep problem

Hey i have a 1997 jeep wranger. 4 cyl, automatic with 97k. sometimes when you start it it acts funny......Today i paid close attention.. i started it, the RPM's were going up and down(500 to maybe 1300). then when i gave it gas the rpm's would go down( really low, maybe 300 400) and the whole jeep would shake and rattle. so let it run for a min and gave it gas again and it was perfectly fine... i drove off and was on my way. This happens alot after the jeep sits for a few days. But its also done it after an hour of sitting.. its had a tune up( plugs, wires, cap, rotor) 4k ago but we put a new distributer cap and rotor on a few weeks ago. still having problems.... Any ideas would be great.

Thanks for your time Derek

Fuel filter?

Hey Derek:

I posted in another forum, mines a 98, but manual and it does exactly the same. It happened about 4 months ago on my way to work, the RPM's just bounced up and down for about 5 secs. I pulled off the road, turned the car off and on again and continued driving. Never happened again until 2 weeks ago and now it's an everyday thing. It happens just 2-3 minutes after starting the car after it's been sitting for 1 + hours.
My Dad is certain that it's the Fuel Filter, but can't seem to locate where it is so he can see if he can change it by himself without going to a mechanic.

Any Idea's anyone??

Hey, do you have a 4 or 6 cyl? If you do find the fuel filter can you tell me where you found it? Ill look for it too. I posted mine another fourm site and someone said it could be leaky fuel injectures. But mine happens right at start up... Thanks

the fuel filter on these models is not replacable - it is located in the tank and replaced with the fuel pump unit - the actual cause for the problem at hand is the fuel pump - when the vehicle sits the fuel pressure bleed down and it takes a while to build back up after starting - try cycling the key on and off a couple times before starting the engine - this will help build the pressure back up before the engine starts

Thats a new idea! Is there anyway the problem can be fixed? or is it just somthing I have to get use to? Thanks Derek

a few weeks ago before this problem came back, my jeep wouldn't start, at first I thought it was the fuel pump, but it turned out the relay switch was gone. I was so happy I didn't have to replace the pump. labour will be expensive I'm guessing cuz it's in the gas tank.

guess I jumped for joy too long. I'm guessing to solve the problem, I'm gonna have to replace fuel pump :(

tell me how yours turns out since its seems to be about the same as my problem! thanks, hope it doesnt cost you to much....

got an appt monday morning with mechanic. We'll see what the damage is then. I'll keep you updated.

I'm glad I found this thread. I just bought a 1997 Jeep Wrangler. It has an inline 6, 4.0L. Sometimes it has won't start, other times it will start, then shake some, and stall. Sometime it will start right up. It definately has long crank times also.

It seems to be getting worse. I'm thinking maybe it IS the fuel pump? Anyone have any other ideas? Thanks!

okay, i took mine in to get fixed... it came back with a new distubuter and down stream oxy sensor. hope that helps....it was $400 to get fixed

I also have a '97, 2.5L. I was having all of the same problems, long start, shake when start, low RPM when start. It was the fuel pump. The pump was going down and was bleeding the line when the engine was turned off. Had to replace it, $400 due to labor for dropping the tank. Hope this helps.

Hey i have a 1997 jeep wranger. 4 cyl, automatic with 97k. sometimes when you start it it acts funny......Today i paid close attention.. i started it, the RPM's were going up and down(500 to maybe 1300). then when i gave it gas the rpm's would go down( really low, maybe 300 400) and the whole jeep would shake and rattle. so let it run for a min and gave it gas again and it was perfectly fine... i drove off and was on my way. This happens alot after the jeep sits for a few days. But its also done it after an hour of sitting.. its had a tune up( plugs, wires, cap, rotor) 4k ago but we put a new distributer cap and rotor on a few weeks ago. still having problems.... Any ideas would be great.

Thanks for your time Derek
Could be a sensor, maybe O2, which will usually give you low R.P.M, or the idle sensor which gives you high R.P.M. O2 is easy to do yourself, idle sensor I paid for labour but know I know where it goes so will do myself next time.

On The Same Subject, My 97 Jp's Check Engine Light Just Came On. I Tried The On/off With The Ignition, And It Gave Me Code 55, "fuel System Lean", Would This Have Anything To Do With My Fuel Pump? Or Maybe Just The Air Filter, It Is About Time To Replace It. Thanks

If it is running lean then it could be a sensor, if the sensor is burned out, either your o2, which reads the oxygen coming out of engine just below the manifold, it will tell your computer to adjust the mixture to engine, should replace these once a year anyway, easy to do yourself. If it is idle sensor burnout it will also tell your computer to adjust the engine mix, can't stand sensors.

thanks fro the post, however, after driving it home yesterday i encountered the "new" problem. started fine, pulled off fine, but when it came time to stop the rpm's dropped to almost nothing and there was a noticable shimmy. so i am thinking it is probably the fuel pump, like everyone else.

hey, i finaly got my jeeo running correct. the problem is in this bulleten by jeep. "dtc $77- fuel system lean idle shake hesitation" It involes repalceing the fuel rail and reporgraming the computer. It cost me 427 odd dollars at my jeep dealer. Only jeep dealers can do it becuase of the softwear. Now my jeep runs perfect and when you romp on it, it has more power after 3,000 rpms. This bulleten is for 1997 jeep wranglers with the 2.5. If you have this problem call you dealer and ask them.......... about it!

oh yeah my first repair of $400 with the distrubter and stuff did nothing.......

Great info on this problem. I have experienced all of the above. (The first time I'm sorry to say on a 7 hr trip back from Myrtle Beach, SC)
Have any of you had to replace the gas tank itself along with the fuel pump? My mechanic said that he called a local jeep dealership in town and that is what they recommend with this problem. (This particular dealership actually keeps two wrangler gas tanks on hand at all times for this problem) Any information would be greatly appreciated. Thanks.
James Adams

Just some info... the 97's and I believe the 98's as well, have a fuel sending unit recall on them, go to the official jeep site and type in your vin, it will tell you if the work has been done yet. if your jeep has the recall, it gets done for free!

Hey Guys,

I have a 97 Wrangler with the 2.5 in it, my problems were similair. When I tried to drive mine or give it gas it would just bog down and die if I didnt pat the hell out of the gas to get it going, but mine would idle ok. Just wouldnt run for nothing. My problem come to be the fuel sending module, around 700.00 for the part. But it runs good now so I guess I am content..

Just my two cents

Hey i have a 1997 jeep wranger. 4 cyl, automatic with 97k. sometimes when you start it it acts funny......Today i paid close attention.. i started it, the RPM's were going up and down(500 to maybe 1300). then when i gave it gas the rpm's would go down( really low, maybe 300 400) and the whole jeep would shake and rattle. so let it run for a min and gave it gas again and it was perfectly fine... i drove off and was on my way. This happens alot after the jeep sits for a few days. But its also done it after an hour of sitting.. its had a tune up( plugs, wires, cap, rotor) 4k ago but we put a new distributer cap and rotor on a few weeks ago. still having problems.... Any ideas would be great.

Thanks for your time Derek

Hello dude. Hey man i know this a pretty damn old Message. But i just sing in for this, and i saw your message, and dude thats exactly what is happining to my jeep. So if you can help out, on what you did to fix the problem, that will be great. thanx dude.

migi

I don't know if this helps but I had an old Cherokee that would start up and idle would fluxuate as well. One day it took a long time to crank and the idle fluxuated again and then the vehicle died. wouldn't fire at all after that. I opened the hood and smelled fuel which sent me right to the fuel rail. Easiest to check from the top. One of the "O" rings on the fuel injector had gone bad and was spraying fuel all over the engine compartment. After removing the fuel rail I replaced 3 of the 6 injectors, and cleaned the others. After that it ran like a champ again. Hope that helps

by the way my Cherokee was the 4.0 L6. I don't know much about the 4 cylinders