QuestionQUESTION: i replaced: plugs, : plug wires, : dist. cap, : rotor, : o2 sensor, : egr valve, : air cleaner, : all vacume hoses under hood, : cleaned throttle body injectors w/ carb cleaner real good, : tightened down throttle body hold down bolts, : sprayed carb cleaner on every hose and possible place of vacume leaks, (to no avail) but, i cant find the problem, and its thus, i have a missfire or stimbling on very low throttle, then it dissappears, sometimes it shows up at low speeds if i roll the throttle on lightly, but, if i jump on it big time, with the tranny downshifting hard, it goes good. this problem really rears its ugly head when i have the air cond. on, and yes the solonoid is kicking out correctly compensating for the load. the only thing i have not done yet is replace the fuel filter, but, it looks like i have good flow. this thing is really getting to me, i have checked and rechecked the codes, but come up empty. on a side note, i replaced the plug wires with m.s.d. dual core performance wires, please tell me i didnt waste my money and that these are causing the problem. this is my moms car and im looking pretty stupid, though ive been working on cars for 30 years. it is a 1989 cadillac fleetwood "g60 special" front wheel drive w/ a 4.5 litter v8 w/ D.F.I. HELP ME PLEASE, IM AT THE END OF MY ROPE, THE SAME ROPE THEYRE FIXING TO HANG ME WITH! THANX
ANSWER: Is the stumble more pronounced when the engine is cold or at normal operating temp ?.
If there is any carbon buildup on or around the throttle plate area, Clean it out.
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QUESTION: the problem is happening all the time, but, is more pronounced when the engine is hot, a big time differance, when hot, it is always there
AnswerIf there is any carbon buildup on or around the throttle plate area, Clean it out.
IS or HAS the check engine light ever illuminated on the dash ?. Did you check the computer for any CODES ?.
Partially restricted EGR passages can also cause stumbling as could a weak EGR valve.
