Dino Gas

1990 Pontiac Sunbird Running Rough and poorly...?

Here's the story,...bought this car a year ago off craigs list, drove it home about 1 1/2 1 way ran like new. 6 months later started getting vaccum leaks from the rear of TBI ( Throttle Body Injection ) and I replaced all hoses. didn't change anything after driving it everywhere around town etc. now another 4 months later it's barely running at all, blowing blue-black smoke only when I step on the gas, cars overdue for inspection, and 2 garages can't keep it running long enough to put it through the dino machine test. they told me they'd start with giving it a full tune up...and said it's running way to rich, but wouldn't tell me why without paying $95.00 for the diagnosis. I don't wan't to junk it...I just put $500.00 into it, with exhaust, cv joints, valve cover gasket, pvc valve, fuel filter, air cleaner, temperature guage etc. today it's raining out here, and it would't start, dry day's it will usually run ok. when it feels like it, so what should I do? it's got a 2.0L TBI

Normally I disagree with people who first suggest changing spark plug wires, but I have to agree with Moises M here. Humidity will increase the potential for a short in the secondary ignition. It may also be a good idea to change the spark plugs as well in case the ceramic portion is cracked.

This is a pretty unusual case. You mentioned vacuum leaks first, but that would make it run lean. Then you mention that it's running rich (which black smoke confirms).

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