problem when under boost

[WIMSPWI]

the car seems to run fine when i'm not under boost, but once the turbo starts to spool the car starts hesitating pretty bad and it sounds like backfire out of my exhaust over and over again....any idea why this could be? its almost like a rev limiter exhaust rumble sound when i boost and the car hesitates and will not keep steady. any info is appreciated. thanks

[Packerfan]

Whats the Temperature where you are

[terbow]

does it idle bad? do uhave a boost gauge? if u do, wahts ur idle vac?

a leak will do that. im not sure of ur mods, but if the vac is less than -20 then check all your pipes.

[brmiley]

check your egr valve..possibly needs cleaing or replacment. mine did.

[bazooka joe]

check your egr valve..possibly needs cleaing or replacment. mine did.
my experience with egr's...it's more a bad idle problem??? under boost i'm not sure you'd know the egr was bad or dirty

[brmiley]

Not so much...a broke egr valve is a leak..which means is a vac leak..which can cause problems when boosting..like it cuts out or something.

[WIMSPWI]

its like 50 degrees here, and i have a -20 to -21 vac at idle... the gauge does go from 8 to 7 to 8 ect. when the problem is occuring....as if i had a leak, so i'm gonna try to figure out where i could possibly have a boost leak.

any other ideas?

[DiscreetSpeed]

Sounds like fuel-cut or boost leak.