sun_q

Hi All,

Here's hope that someone can help me diagnose a problem.

My 2000 9-5 Aero (5-speed) vibrates (or "shudders") *only* when accelerating. A good example is bringing the car from 50 to 65 or 70 mph in 5th gear.

As soon as I let off the pedal, the vibration stops. Also, no vibration when breaking or cruising. Tires were recently replaced with alignment, etc. by a reliable mechanic, so I don't think the problem is here. Problem reappears as soon as I give it a bit more gas (e.g. going up a hill on the highway.)

I suspect it's a problem is with the clutch (suggested by a forum member: "clutch hammer", although I'm not sure what this is) or turbo: The problem comes up only when turbo kicks in, usually as I pass into yellow and then red on the turbo dial. (And, again, most noticeable when accelerating up to high speeds.)

Also, recently the turbo air intake tube popped off on account of an old clamp. A quick fix put it back on securely, but perhaps a bit of dirt/gunk, whatever made it's way in before I fixed the problem?

Any guesses and/or suggestions? Ideas for further diagnosis?

Thanks again to anyone who can help.

Best,

Eric

Roto

your turbo meter's needle goes far into the red zone?

sun_q

Hi Roto,

Thanks for the reply! Yes, the turbo goes well into the red zone.

What do you think?

Best,

Eric

Roto

something is wrong...and what you're describing sounds like the fuel cut. Is the check engine light on? The needle is never supposed to go well into the red zone in a stock car. The boost control valve may be gone bad or the wategate is getting stuck closed... one way to diagnose this is to bypass the boost control and just connect the wastegate actulator to an unobstructed vaccum source. If you still just into the red than it's the wastegate, if not than the electronic valve is bad.