My friends '98 GST spits and sputters when it gets to about 3000rpm, he is running 12psi. He says its not the fuel pump and he already changed the fuel filter, spark plugs, and wires. I think its the fuel pump. Any input would be appreciated.

 

boost leak

 

mine did that when i bought it. it was bad gas. a few tanks of premium gas and injector cleaner fixed it right up.

 

boost leak, make pressure tester find leak, what kind of acceleration?

 

any codes?

 

boost leak

 

Check the ecu. DSM ecu's tend to go bad. try an ecu from another gst and see if that fixes it.

 

ok well i dont think its boost leak but i dont know, he never uses anything but 93 octane and he already ran a bottle of injector cleaner. it has a check engine light from when he did all his mods, we dont know which one cuz we put everything on at once, so i dont know how to check codes on a dsm so anyone who does let me know. thanks

 

what kind of mods, and we are telling you "it's a boost leak" we are all about hmmm.... 99% sure. if you have an HKS BOV the leak is comming from where the hose connects to the bov or the flange.(personal experience)

How to fix Boost Leak-
1)Make pressure tester (5$)
2)get air compressor(borrow or use pump for basketball)
3)put tester on run air through fix leak.

 

just go to autozone and have the code pulled, its free. Its prolly just an o2 sensor or something irrelavent like that