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Warm engine misfire

engine runs fine cold. as it starts to warm it starts to miss. surges at idle. acts like it is starved for gas when trying to accelorate on the road. or when trying to rev the engine while standing still for that matter.

OBD1 car so we can pretty much forget getting help from an onboard system (I have not been helped very much by the ODB1 system). We can look at what happens when a car warms up, what comes to mind is it leans out. So saying this problem is caused by a small vacuum leak and the system its self compensates while car is cold would be fine if we only have issues at idle, but we have them at speed.

I am still thinking of a mixture problem that turns into a flat out miss when warm. Not to put the cart in front of the horse my thoughts are based on the idea that no primairy or secondary ignition issues exists (in laymans terms “the car does not need a tune-up”). That being said perhaps an injector with a really bad spray pattern is the cause. This may be one of those rare times an injector cleanse would work out as being worth the money. I repeate, you must make sure all tune-up items are taken care of before getting into the fuel system.

This car still has a distributor. You probably need a tune-up. I’m suspecting new spark plugs, ignition wires, cap and rotor would help out a great deal. The reason it seems better when cold is the enriched fuel mixture and elevated idle speed is probably masking some of the issues.