For the past month my car has been hesitating a little to start, and sometimes I have to crank it twice. Then if I go for a drive, the car runs sluggishly and shuts off at around 2500rpm.

Today I figured out part of the problem when i had to pull over cause that sucker shut off on the highway on-ramp

Seems that if I take the gas cap off and let it make it's usual "hiss" sound and then put it back on, the car works great until I shut it off and start it again.

So, should I:

1: Stop using cheap gas (i'm poor)
2: replace fuel filter
3: install a vented cap
4: plan to replace my fuel pump
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'89 IROC-Z
5.7L 350
B&M shift kit
Flowmaster exhaust
Crane cam
Adjustable fuel regulator (I think B&M)
G92 option package

 

well in terms of the cheap gas there are lots of debate on what octane for our motors but (i always get this mixed up in my head so forgive me if i get it backwards) Too low of an octane is going to result in early detonation and pinging which doesnt sound like your problem. This is going to drive me nuts because ive heard this problem a number of times and i forget exactly what it is. Someone will chime in soon. I'm pretty sure it has nothing to do with any of the things you mentioned.

 

i have no idea if your problem is related to the pressure in your gas tank or not but if you do have excessive pressure this is how to fix it. This is not my writing so dont ask me questions about it


"You probably have a problem with your canister vent line. The fuel that returns from the fuel rail is hot, when it gets to the tank it heats the other fuel causing pressure. This pressure is supposed to vent to the charcoal canister where it is absorbed by the charcoal then pulled from the charcoal into the intake to get burned. This way the fuel system is closed and no gas vapor (emissions) get to the atmosphere. Your vent line to the canister is probably kinked. Most likely when they reinstalled your fuel tank. If you get a shop manaul it should tell you how to identify the vent line and test for restrictions. Some other people on this site know a link to a diagnostics page. I haven't used it but have heard its good. Another problem may be your canister itself. If it is plugged it will not vent properly. But, since you said this happened after the fuel pump install, I would go after the vent line first. Hope this helps."