psk628

Hello,

I've got a '95 GT Convertible that I bought new, now with 130k miles in great shape. Was recently running a bit off and, based on codes, found a bad MAF sensor, plus replaced plugs, wires(found a bad wire), rotor, and cap. Ran great for about a week. Suddenly, it will not idle and has no power above about 1/4 throttle, but so far, only after driving for a few miles. Replaced the fuel filter which seemed pretty restricted. Drove fine for about 10 miles then started acting up again. Seems perfectly smooth at 1/4 throttle (limping home), but no power above that and won't idle at all. Check Engine light does not come on at all. Fuel pressure was fine in the garage, but I haven't been able to check it when it was actually acting up. Any thoughts?

Thanks,
Dave

64bit

check your TPS voltage. on the 94-95 cars, if the TPS fails, the computer will drop into a limp mode and wont accelerate or run properly. I had two fail on me in that same manner.

jwog666

do this and record your flash codes, and post em

psk628

So. I've pulled the codes 3 times. All 3 times the KOEO indicated 111(system pass), 113(ACT over voltage), 157(MAF under voltage). I'm quite certain that the 113 and 157 are codes still retained from prior to the MAF replacement a few weeks ago (unplugged the ACT while testing the MAF, that's what triggered that error). The KOER was a bit different.

1st test - engine cold generated 111 and 116 (ECT out of range)
2nd test - drove about 15 miles. About halfway through the drive, symptoms appeared; stalled at idle, no power above 1/4 throttle. After about 2 miles, started working normally again. After pulling in the garage ran the KOER again. Only 111 passing.
3rd test - engine cold generated 111 and 116 again.

I'm going to stop and pick up an ECT sensor, but I have a hard time believing an errant reading from that is causing the drastic symptoms I'm seeing, not to mention the odd (system pass after exhibiting symptoms) that I see. BTW, symptoms come on slightly subtly, not an abrupt cliff.

I was hoping I'd get it back to the garage while exhibiting symptoms, so I could run the codes and check some voltages, but it's not cooperating.

jwog666

welcome to the wonderful world of OBD1, its no help at all most times. so now , we can say that codes will not help with diagnosis, because its intermittent, i would check for chafed/damaged wires that are in the harness to the engine sensors. start the vehicle, let it warm up, and then wiggle the harnesses that run to the sensors on the engine, while doing this be careful not to put your fingers anyplace that will remove them, and pay attention to any changes in how its running. if you notice a change while wiggling a certain harness/connector focus on making sure you can duplicate it repetedly, you may find that a loose pin in a connector, or a damaged/pinched/corroded wire is to blame.