Hey guys. I have a 1997 jimmy sle 4 door. I have been reading through other threads and found some good leads but no realy good answers. my jimmy starts and runs perfectly at idle, and if its in park and u push the gad to the floor it revs up fine. It has no sputter and runs smooth. My problem is mostly in 1st gear, when I start out in first gear and give it a good amount of gas it just won't go and the engine seems like it starts to sputter and will slowliy jump from about 1500 to 2200 or so rpm then will seem bogged again and at about 3500 rpm the engine seems maxed out and won't be hardly moving, at that point if I let off the gas a bit I wil shift hard to 2nd. Same problem here but not as bad.

If I start out slow and just eas on the gas it will drive and shift fine, and it seems if I start slow untill I get to 2nd gear then give it some gas it will respond a little better.

I have checked the plugs and wires they are not old and are ac delco so I have ruled out the bad bosche wires, plus it doesent rattle like it would if it were misfiring. I just replaced the fuel pumpand filter yesterday and still nothing. The only thing I could think is could it be the torque converter or the cat? I have no ses light so I'm thinking its not the cat.

Any help is greatly apreciated. Thanks

 

My guess would be the cat. A clogged catalytic converter will choke off the engine, limiting RPM. When in park or neutral, the engine does not need as much airflow to rev freely so RPMs can get higher. When under load, the airflow through the engine is higher which is more affected by the restriction.

As a diagnostic point, try removing the O2 sensor directly ahead of the catalytic converter and see if the problem remains the same. If it does not, the catalytic converter is the most likely culprit.

 

Thanks i will give that a try tomorrow. i haven't driven the car in a while so it never really got warmed up when i would test drive it.. i let it run for at least 2 hours today in the driveway with some lucas in the tank to clean the injectors a bit, and after it was hot i gave it some gas and noticed that it would sputter at the low rpm when in park. would the cat cause the engine to do that in park after its hot?

I decided to pull all the plugs and wires replace all the filters and oil and pcv valve since it has been sitting for a while, in hopes that that will eliminate any other problems..

Thanks for your suggestions..

 

Did replacing the CAT fix this problem? I'm having a similar one