haven a problem with my 87 iroc

[DoinItInAThirdGen]

ok i have the 5.0 TPI.
after about driving for an hour or two, my car will bog and the fule pump gets really loud for about 10 seconds and my car will just shut off. i go to take off the fule cap and the tank is under so much pressure the top just wants to blow off.
so im forced to sit there for at least 20 to 30 mins.

if anyone can help me figgure out what this is, it would be great cuz i dont have a clue.

i dont think it could be the fule pump cuz i just changed that out like a little over a year ago.
thanks

[hotrod_chevyz]

If the fuel pump is making noise it might be shot, and being new doesnt mean it was right to begin with. You might try just replacing the gas cap. If thats no good then you have a gas tank vent line problem

[DoinItInAThirdGen]

yeah someone was trlling me that it might be the vent under the rear driver-side tire that might not be opening, so it might be causing the tank to pressureize

[hotrod_chevyz]

Im used to the problem being opposite of what your saying but thats doesnt make a difference i guess. Still has to be a problem with getting the tank vented.

A typical problem with the vents would be as the gas leaves the tank the space isnt replaced by vented air, causing a "-" pressure not a "+" pressure.

[Blue Bowtie]

Check the tank pressure control valve next to the EVAP canister:



The valve is designed to vent to the canister and intake at 1 PSIG, and to vent to the canister alone at extremely low pressure. If the EVAP canister is saturated or plugged, the tank can build pressure. If the tank pressure control valve is damaged or connected incorrectly, the tank can still build pressure.

The vent valve in the fuel fill cap will only relieve at several pounds of pressure, far above where the tank should really operate.

That valve above the tank is a surge/pressure relief valve and is only designed as a safety in case of rollover, serious rear collision, or fire. It should NEVER open under normal conditions.

[DoinItInAThirdGen]

thank you guys very much! i will check this problem out and so if thats it.
i will write back and let you guys know
thank you again very much