Just a little back ground about my 1997 Grand Cherokee laredo before i get started with the current problem.

I bought the jeep used a few years ago with 140k miles and a check engine light on. The guy I bought it off of said the CEL was just a bad o2 sensor. Ended up replacing both sensors along with doing a full tune up.Plugs,wires,cap rotor and coil. After that the CEL went away for about 2 weeks then all hell broke lose. Started having surging issues along with misfires and a bunch of other not so good stuff. Ended up replacing the fuel pump along with the throttle position sensor, Crank shaft position sensor and idle air control valve, engine coolant sensor and that seemed to of fixed the issue until this week.

When I go to drive the jeep in the morning it runs horrible not sure how to describe it other then it feels like its misfiring it will idle fine then have a hiccup and then idle fine hiccup rinse repeat. When I press the gas peddle down it will hesitate and kinda buck when I press down the peddle until I get on the highway then its ok. And once it gets into late morning or early afternoon it runs fine. I am completely lost as to what the problem could be. Any help would be appreciated.


Chris

 

what was the problem? was it bad plugs? or bad CAT?

 

Ive just replaced the plugs and wires and the cat and muffler have been removed and replaced with a thrush turbo muffler. Still does the weird idle when its first started for the day. But I just found out ill be getting a 96 cherokee sport 4x4 next week for free so I just need my 97 GC to run for 7 more days *crosses fingers

 

My XJ was having idle issues first thing in the morning until it warmed up and my mechanic friend suggested maybe it was the idle air control sensor. Didn't fix my problem but who knows.

 

It wouldn't surprise me if that's the problem, But like I said im getting a 96 cherokee sport here sometime this week so Im happy =) I like the Cherokee sports better then the Grand Cherokees anyway

 

Mines have always done it first 10-20 seconds on first start up. Never looked much into it.. Runs great after that

 

If the vehicle runs OK from cold in the afternoons – it might be moisture condensation from the cold night air.

Try giving the engine bay electrics (especially the spark ignition circuits) a liberal spray of WD40 (or similar) and see how you get on.

 

i actually have a extra computer for a 1996 , that i want to sell if your interested.