91 Excel 5spd EFI
Looses power and RPMs cold or hot while accelerating or coasting or de-celerating. more than just hesitation, car bucks repeatedly (several times) or just 1 to 2 times, then runs fine for a minute or several minutes then bucking (in any degree) returns. I vary the throttle or shift into another gear when this begins and most-of-the-time can manage the bucking that way. If i mal-adjust (turn-up) the idle the bucking almost goes away - BUT the car REVs between 1200 and 1800 when at normal opperating temp. AND idle at 1600 on first start-up then slowly lowers to 1200 and as coolant temp. increases towards normal the REV (mentioned above) slowly takes-over the idle. Also the ISC Motor "hunts" in BOTH cases (idle set to factory specs or mal-adjusted to compensate for bucking). PARTS REPLACED = factory plugs & wires; timing belt & tensioner (timing set to factory specs & verified by factory trained tech). PARTS TESTED = afs assy (afs + iats + bps); injectors; isc servo assy (idle swk + mps + motor); tps (all tested OK per 135-page online shop manual at "hmaservice.com"). Additionally, the MIL never turns-on nor are there any Codes ever set by this bucking or for that matter when the idle is maladjusted to compensate. HELP PLEASE.