Ok first thing to look at is 200,000 miles. That engine is well worn so unless this is a clearly recent problem and the car has been running fine up until this point then I would go through this checklist here (before you do this make sure the catalytic converter and egr are functioning properly. Are you absolutely sure the mixture is correct.->
1. Buy a vacuum guage and a tee so you can put it on the manifold. CCV line or the line to the QuadraTrac is good. At idle the guage should be steady 16-20 in. Vacuum. If it is low or erratic take note of that.
2. Test compression of each cylinder with a compression guage. Disconnect the coil wire from the distributor and have the carb at Wide Open Throttle. Crank the engine for 3-5 sec. And record the best reading for each cylinder. They should all be around 120. No cylinder should be more than 20 psi lower from the highest and all of them should be above 105 psi.
3. After that you should consider timing to be an issue. If nobody has checked this or changed it ever then this is exactly what is wrong. The chain is either worn or has possibly skipped at tooth. When you rev the engine does it hesitate because sputtering and stalling is extremely close to hesitation. You can try to check and see when teh valves open and close by pulling the valve cover off, taking all the spark plugs out and noting on the crankshaft timing marks when the valves open. You should see the rocker arm move. These marks will be 5, 10, 15 degrees TDC and ATDC (Top Dead Center and After Top Dead Center) Note when the valves begin to open and close and compare the readings in a chilton, haynes or the original factory manual. (Not the glovebox phamplet) If you are going to keep this car please go and get a factory manual straight from jeep. It is 400 pages of everything all the models of that particular year. Very in depth. An AMC engine manual for the 2.5L is great too if you can get one.
Just let me know if you need more indepth help because this is not an easy challenge.
Tuesday, May 6th, 2008 AT 1:20 AM