Pressure under gas cap

JASONR015

MEMBER
PONTIAC FIREBIRD

1996 Firebird 3.8L V6. I have a problem with air pressure building under the gas cap which really decreases the power. When I loosen the gas cap the air hisses out and the power is back. Thank you.

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Sunday, June 3rd, 2007 AT 4:50 PM

3 Replies

SERVICE WRITER

CERTIFIED MECHANIC
9,127 POSTS

Are there any codes in the computer?

Sounds like an evaporative cannister purge solenoid problem, not allowing vapors to be purged.

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Sunday, June 3rd, 2007 AT 6:58 PM

JASONR015

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2 POSTS

Nope, no codes.

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Sunday, June 3rd, 2007 AT 9:04 PM

TBDK

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24 POSTS

The problem could be as easy as your gas cap. The gas cap has or is supposed to have vents that allow air to enter the tank as gas is pumped into your motor. If your cap doesn't have vent or they have some how become clogged(I have no idea how) then the air would be able to enter the tank. I would try with the obvious. If you have another car, swap the gas caps for a bit and try it out. If you don't, you may have to pony up the cash for a cap. Ranging from $10 to $30 depending on the type you want(lock, no lock, brand name, etc.)
Good luck fixing your problem.

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Wednesday, June 6th, 2007 AT 1:11 AM