k, well #1: I just got my car back from the shop after having my fuel pump replaced and my gas cap was missing. Could the lack of a Vacuum in the tank cause fuel starvation i.e. hesitation when getting on the petal and a kind of "chugging" when moving from a stop. #2: I've got an idle problem, very mild cam but she runs very lopey. wondering if leaking valve seals could cause this by fouling the plug.

 

The gas tank/fuel system is pressurized, not, umm... vacuumized. heh

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89 iroc-z 305 tbi
k&n filtercharger, open element air filter. nuffin' else

 

Welll, if the gas cap were off for any length of time, then it's possible you got a good bit of moisture built up in the tank, and that would cause you some temporary problems, like the rough idle and stumble you described. And of course, check the plugs if you suspect any fouling.