z284pwr Posted June 23, 2005 Report Share Posted June 23, 2005 This originally started out as a really bad hesitation off idle...anyways, here is a little background After finally getting the exhaust done in hopes it would fix the problem, still having this problem....Off idle, to WOT the car hesitates pretty badly, ha, real bad . And basically anything before about 2500 under WOT is worthless, its a slug and worse than a stock N/A 3.1/Auto pretty much plus brake torque/power brake will only net ~1800 RPM total and still sluggish up till about 2300 RPM .....Here is a little info to help possibly remove some possibilities '90 Turbo Grand Prix Built "3.2* Engine, basically custom everything, in other words FAR from stock... Jeff M Crossover and TopGun 160 Chip New Full 2.5" exhaust all the way back Fuel filter has no more than 5k miles, fuel pump has been replaced, dunno when but it has. All new plugs/wires ACDelco plugs of course, Accel Super Stock custom to length wires. Injectors were sent to be cleaned, only to discovered ALL 6 were junk....so, 6 brand new injectors have been installed. No vacuum leaks, verified with pressure tester. so problems include.....stumble off idle, and poor accleration below 2500, datalogging it, I couldn't find anything out of the ordinary at all? Before or after the injector swap except it won't idle smoothly anymore, stumble got worse, dies sometimes, it had been showing DTC error 23 *Low MAT*, swapped IAT sensor, no help, swapped TPS, no help.....lost.... OH!! OH!!, its gets better. It has been developing a really strange thing....under acceleration it goes basically ape shit! Speedo drops, engine basically dies/stutters REALLY bad, Service Engine Light and Low Coolant light comes on, sometimes when I put it in park, it will rev to 2500 or so and slowly idle back down. Even sometimes just cruising down the freeway, anytime I got about 80, it did the same thing, and even doing about 70 tonight. Doing a datalog, when this happens, it loses transmission and signal with the PCM. So no info during that time? Is this a sign of the computer taking a long slow death? Quote Link to comment Share on other sites More sharing options...
jdcutty Posted June 23, 2005 Report Share Posted June 23, 2005 Check all of your major ground connections. Poorly grounded components can make everything go nuts. Otherwise check for shorts or bare wires. Quote Link to comment Share on other sites More sharing options...
Supreme Cutlass Posted June 23, 2005 Report Share Posted June 23, 2005 One thing that helped me fix some minor hesitation was cleaning the throttle body out. You'd be suprised how much junk can get in there. If you haven't already, you might want to clean it out and see if it helps any. Sorry, I don't have a definate answer. Quote Link to comment Share on other sites More sharing options...
Jcrow Posted June 23, 2005 Report Share Posted June 23, 2005 bad ECM? They are known to go bad. The factory coated the boards in a clear plastic that over time pulls the traces off the board Quote Link to comment Share on other sites More sharing options...
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