I recently purschased a 1993 4-runner with a 3.0 litre that isn't running right. It may run ok for an hour or maybe only a few minutes, but when it begins to run wrong it idles really rough, smokes black (as though it is running really rich), then dies. I have checked for codes in the computer but it isn't setting any. I was wondering if anyone else has had a problem similar to this or has any ideas?

 

Valve not seating corectly at high temps?

 

Do you mean an intake or exhaust valve not seating properly once the engine is hot? If so, I don't think that is it because it runs goofy cold even sometimes. I was thinking maybe the afm is bad but I think maybe that would make it set some kind of code and maybe not be intermitant like it is. Anyone have a afm for this thing they wanna sell?

 

Anyone have any info on the cold start injector? I didn't know that these had such a thing. Could this possibly be the problem?

 

Its likely an electrical part such as a defective thermal time switch, throttle position switch, etc. Something is telling the computer to turn on the cold start injector when the motor is warm. Ditto for the fuel pressure regulator but much less suspect.

My $0.02

 

Do you have any info or know where I can find any info on what actually tells the cold start injector when to fire and maybe how to check these things?