After opening the gas cap, there is alot of vapor escaping from the tank. Is this ok? Should I drill a small hole in the cap so it does not build up? Thanks

 

There is a vapor vent system on our cars. Yours is probably just not working correctly. There is a metal line that goes up with the fuel line and a plastic canister which it goes to. When yo uare on the highway and you let off the gas quickly, the vapor is released from the canister and burned off. I am not familiar wit hall the details of your vapor system, since your car's an L98. I only know my carbed setup. I dont recommend drilling a hole in the gas cap, though.

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1983 Firebird
TH700R4 Auto
Small Block 400
LG4 ECM, Intake, Carb, Distributor, etc.
Soon to be non-computer.
Clarion Head Unit 45X4
2 Pioneer 400W 12" Subs
Third Gen Performance
"A four cylinder is half an engine."

 

You may have a plugged or overly saturated vapor charcoal canister. Some of them have replaceable filters on the bottom of them while most don't. Smell it, and if it smells really strong of gas, then you need to replace it. Do not drill a hole in the gas cap. SOme vapor is normal on warm days especially, or toward the end of a tank of gas. My guess is you have a pretty plugged up canister though. They are like around $50.00 new since you have to have emissions where you live. You can do the "smell" test at a junkyard and probably get one pretty cheap as well. The canister has charcoal in it that absorbs the vapor from your tank and then reintroduces it to the engine to be burned again....so in short, it makes your fuel economy better, and your car run cleaner.

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Formerly known as 1984L69Z28

1984 Z28 - L69 optioned, 350HO w/ Trick Flow Heads, Drop Forged Lunati Crank, Crane Cam and 1.5 Roller Rockers, Stock Z28 Intake Manifold, Highly Tweaked Rochester Carb(700cfm), K&N Filter, ThermoMaster Chip w/ 160 Stat, Comp Headers, 3" Stainless Dual Exhaust w/ no Cat & Dynoflow Muffler, 4 wheel disc brakes, etc....

God bless us father, son, and holy ghost....whoever goes the fastest wins the most!!