Just had smog performed on my car, barley passed--smog guy said my car isn't completely burning burning fuel---he could not tell me why. anyone have any answers? what causes this?? It is an 89 IROC with TPI....thanks...

 

Is the check engine light on?

Does the car run rough?

 

My car runs great--although I have noticed at times that if I am idling for a while, and turn the car off--I smell gas...

 

Maybe a leaky injector? a torn diaphram in the Fuel Pressure regulator?

Gunna have to dig into it man

 

Probably was meaning that the HC levels were high.
Old plugs, wires, cap, rotor, can contibute.
As well as the oil being old and somewhat saturated with combustion byproducts.

Sharp guy with a good scope could check out the ignition easy enough, but $$$.

 

If it passed, I wouldn't worry about it.

 

Any number of things can cause it. Time for a tuneup. Start with the ignition system, finish with fluid changes and new o2 sensor.