Contour Enthusiasts Group Archives Forums General General gas tank pressure

when I take off my gas cap I NEVER get the pssssst of pressure releasing; I wonder if that is a problem and is causing my sometimes hesitation on acceleration? any ideas?!

I had a severe hesitation problem back in May, turned out the check engine light came on a bit later and it needed a new O2 sensor, fixed the problem.

just movin this back up... ideas?

the hesitation is under hard acceleration and normally in the higher rpms. When the car is first started it acclerates fine, but after driving awhile it starts to run flat under acceleration. RPMs rise there just isnt much pull. I have already done all the "how to's " except change the fuel pump.