Stuttering only when boost hits..tried the basics..

[bobby98gst]

1998 GST 171k miles 5sp

mods are 16g with dump tube,intake, catless with hks super dragger muffler, ngk bpr7es with ngk wires, 550 cc injectors and walbro 255 fuel pump, 1g fuel rail. The car has had the above mods for 2 yrs and it ran perfect. I change the plugs every 5k miles.


I was in the yesterday running the car through some turns and it was running great and boosted great.. came out of a turn and gunned it and it just suddenly started sputtering and bucking but only under any type of boost. The car starts fine and idles fine.. The car even runs fine as long as you dont hit ANY kind of boost.

I checked the plugs..they are fine
I replaced the wires..the problem still exists
I checked all hoses and intercooler piping and everything is snug
I looked for any kind of spark in the dark from the coil and nothing (maybe this is the problem though?? Coil pack has never been changed)

Any suggestions on where to look or what to do?? The car is boring as hell w/o boost.. I cant even get on the hwy w/o stuttering some! Thanks!

 

[robbo185]

when you checked the pluges, did you check the gap on them?

 

[Bluefire16]

Ok, so sounds like a boost leak....so you didnt do the basics....80% of the time our problems are due to boost leak.

 

[bobby98gst]

Ok, so sounds like a boost leak....so you didnt do the basics....80% of the time our problems are due to boost leak.

It turned out being a gash in one of the hoses that runs from the intercooler to the turbo..it was rubbing against one the fans and it finally took out the hose.. cheap fix!

 

[Bluefire16]

^^ so a boost leak...