C4 sputters in OD under load

[Ajetsprt]

Hi
I have a 1992 C4 coupe automatic and it starts and runs perfectly fine in drive. When I have the car shifted into overdrive which is how I've always driven it the car is fine until it's in 4th gear. Once in 4th and you start to put a "slight" load on it like a gradual incline or if I lift my foot off the gas then slowly accurate again. The car starts to sputter and vibrate possibly even misfire until it down shifts. Once in 3rd everything is fine again till the next time. I can't remember for sure but I think last year before I put it away it might have even backfired during one of these episodes.

Any ideas where to start on this or what to look for?


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[1cooldaddyo]

My personal rule of thumb is that missing under load is almost always ignition related.
Check plugs, wires, and optispark.

 

[Ajetsprt]

Any recommendations on where to get a replacement for the optispartk? This only ever happens under a load while in 4th gear in the overdrive position. Never does it in Drive


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[ecss]

Hi
I have a 1992 C4 coupe automatic and it starts and runs perfectly fine in drive. When I have the car shifted into overdrive which is how I've always driven it the car is fine until it's in 4th gear. Once in 4th and you start to put a "slight" load on it like a gradual incline or if I lift my foot off the gas then slowly accurate again. The car starts to sputter and vibrate possibly even misfire until it down shifts. Once in 3rd everything is fine again till the next time. I can't remember for sure but I think last year before I put it away it might have even backfired during one of these episodes.

Any ideas where to start on this or what to look for?


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Here's a thread about a LS1 that has your symptoms. He diagnosed it as a bad torque converter. I suppose it could also be a bad torque converter clutch solenoid.

If you have a volt meter you can place your red probe on pin F and black probe on pin A of the diagnostic connector. Set meter to DC volts. Warm the car up and go for a test drive. When the meter reads zero volts the ECM is turning on the torque converter clutch solenoid. When you apply the brakes the ECM should disengage the TCC solenoid. Monitor that and see if that's when you have the problem.

Misfire under load - LS1TECH