1979-1993 & 94 Conv [Subscribe to Daily Digest] |
I'm getting kinda stumped... New plugs, wires, cap, rotor, ?? Did you clean the coil good when you did all that? Mine is sensitive to dirt & salt, but it's always worse when the engine is cold.
I just looked back at some of your older posts, I'm thinking fuel system now. (Since ignition system is just about all new...) Fuel pressure regulator? I see your O2 sensor isn't too old. The car needs a rich mixture while it warms up, but yours stays too rich? That would explain the black tailpipe & the lousy gas mileage. I suppose it could explain the "coughing" from the muffler.
One thing bothers me is that the ECU will watch the signal from the O2 sensor & adjust the mixture accordingly. Why can't it adjust enough?
FPR is about $50?? (cybertroll.com a couple years ago...) It's easy to replace & probably costs just about that much to get it tested. Unless you've got your own fuel pressure guage set.
I've heard that RTV silicone can rapidly kill an O2 sensor. That's why they make special stuff (like Permatex copper). Did you use anything like that anywhere like valvecover gasket or vacuum hoses?
Vacuum leaks should make the mixture lean, not rich & they leak the most when idling (high vacuum in the manifold). That makes them relatively unimportant during driving, but that also means they don't make your gas mileage real bad.
If you pulled each of the injector wires to see which cylinder is misfiring, did you find one? If its a bad injector then it would only miss on that one cylinder & its spark plug would look a lot different than the others. OTOH, stuff like airflow meter, fuel pressure, etc. would affect all 4 cylinders about the same.
posted by 131.184.1...
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