2004 SAAB 9-5 2004 SAAB 9-5 - Turbo inconsistent

JIMMMMINY

MEMBER
2004 SAAB 9-5
4 CYL
FWD
AUTOMATIC
150,000 MILES

Occasionally, when I am driving on the highway, the turbo will sort of rev up and down on its own rather than being applied smoothly/consistently. This typically happens when I am applying consistent pressure to the gas pedal and the engine is under medium load - for example, going up a gradual hill at a consistent speed (~65 mph). This does not happen all the time, but when it does happen, it usually occurs throughout the duration of a particular trip. Then, if I turn off the car, let it rest/cool and start again, it usually does not reoccur for several days/weeks.

Any idea what this could be or if it's anything I need to worry about? The car otherwise runs fine and has never had any major repairs.

Thanks

1 Reply

MNTHNY4

MECHANIC
612 POSTS

Hey what's up, just a question is this car a AERO model, reason been the only car that I had worked on for the same issue u r asking about was a aero, what had fix the issue was the replacement of the trionic control module. That is the main engine computor [ECM], note did u check all your small vacuum type hoses from turbo pressure valve & turbo bypass valve, note bypass valve at front with long thin vacuum hose running to pressure valve mounted to firewall also get both valve vacuum checked if they hold a vacuum, but anyways turbo gauge to controled by the ECM. GOOD LUCK.