That my 1991 v6 has a bad Ing. Module when it starts right up anytime runs smooth idles fine has no codes clear cat. and mufflers base timing ok and can see it advancing fine to 38deg. with check wire disconnected. ( even gave code for being discon. ) fuel pump readings fine in all modes new fuel and air filters. As soon as you try to accelerate it wants to bog and die.

 

Is this under a load? I assume that it is since you can get it to advance the timing. If the timing is advancing at idle by itself with the wire unplugged you've got a ghost under that hood

 

If this is only happing when the engine is under a load, it would probably be something to do with the MAP sensor, or related wiring, check the vacuum hose going to it that would be the first thing to do make sure its not cracked or missing. Then check wiring to to the sensor. You can check the sensor its self with a volt meter and a vacuum pump, check resitance on the sensor and make a note and check the sensor again with vacuum pump hooked up and pump to about 15-20inches of vacuum and take note, you should se a notible change in resistance! and also check the EGR circut to make sure its working correctly if the map sensor is not at fault!!!!
HOPE THIS HELPS!

 

No I was saying that it all checks out that when incresing throttle timing goes up as it should.
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It does it under load or not checking out TPS today thanks for the info, George.