For a month now my wife and I have noticed that when we accelerate slowly with her car that the car has what feels like a hesitation in it. Especially when going up a hill but it occurs also on level ground (25-45 MPH). It feels like hitting multiple small puddles.

And just recently we noticed what sounds like a loud gear whine coming from underhood. I thought it was the transmission at first but the gear whine is there all the time not just when driving, which leads me to believe that maybe the Supercharger is the Culprit.

Anyone have any idea what the hesitation is and is the gear whine related to it?

Yup, have to agree with Mark -sounds like an electrical problem. Might scan for codes -could possibly be a bad front o2 sensor -mine went out on me in my old 1999 SSEi, but didn't set a SES light.

Thanks for the advice. The car has aproximately 66,000 miles on it. We bought it as a GM certified used car from the Pontiac dealer with 25,000 mileson it (so I don't know if they changed plugs or anything).

Can anyone help with the whine? It kind of sounds like the power steering but it doesn't change when the wheels are turned to the stops, only when you rev the engine.

TA, I'd say you have a mild ignition problem (plugs/wires) made worse by a failing alternator. That'* most likely the whine you hear (assuming it'* not your wife). Typically the rear bearing.

Since you have an SSEi, you may have a transmission problem of some sort. Several of us have had major troubles. In my case, the torque converter came apart. I didn't have the whine you describe, however the car did hesitate and shudder when accelerating. I hope for you that it is something else.

Any SES codes set? All of the suggestions above could be accurate. I just recently ran into the faulty TCC causing similar problems. Does it accelerate fine under heavey load?

Thanks, WILL, I'll break out the stephescope (if I can find it) and listen to the alternator.

The hesitation/shudder is very subtle and onlly occurs during light to moderate acceleration. When at WOT it'* not there. No SES light yet, so I don't think it'* got any codes stored.

My TCC Issue only showed under very light acceleration. Sounds like this may be your issue.

You're lucky. Your alternator bracket doesn't mount to the nosedrive of the SC like the Series 1. Makes it alot easier to isolate the noise that may be coming from the alt. But keep Rogue'* words in mind.