if its a heavy vibration its not plugs/wires. you said its at 55-60 but is it as you are letting off and the tcc would be starting to kick in, or is it before it locks or after as you are cruising?

It did happen to me today at about 40 mph while I was cruising up a hill. I think it is when I am cruising that I have this problem.

Hey Kyle if you go to an automotive supply store you should be able to pick up half shafts for around $180.00or so but that is defietly what it is . you may also need front wheel hubs which are the front wheel bearings but definetly the half shafts . I know here in Ontario I put a set on my 94 SSEi in the summer and I paid $120.00 each. but as I said you need half shefts and a computer diagnostic probably wont trll you that.if you have the right tools it only takes about a half hour to an hour per side they are pretty simple to do.glad to help Eric.

bearings and axles give you constant vibration and noise that doesnt seem to be his problem. i think i would watch the tach. when it happens hit the brake to see if the rpm goes up and the problem goes away with the TC unlocked.

I agree with JW. First thing I would do would replace plugs and wires, along with looking at the contacts where the plug wires touch the coils. I have had the same problem, ended up being a bad plug.

The key thing you described which points to a bad plug/wire is that going up hill the problem showed itself. That is exactly what I had with a bad plug.

Ya a bad plug/wires is what I think it might be and replacing these will be my first step. They should be replaced anyway because they are the original ones and I am at just over 100k.

My problem is when I have about 2lbs boost when I'm just giving it a little gad to go up a grade or hill without really getting into the supercharger all the way.When it starts bucking a little I let off a lttle or give it alot ofgas and it goes away.It kinda reminds me of driving my Goat with Tri-Power. your either running 2bbl or your running 3-2bbls wide open, don't play around in the middle.I asked this question on here when I joined and everybody told me it was my wires/plugs. Changed all that and it'* still doing it over 2 years later. I just live with it or give it more than 2lbs boost.

I bought a left side rem-half shaft a O'Reiley'* $59. Lifetime guarntee.The cv-joint boot was getting bad so I just replaced the whole half shaft.

mrpontiac, did you inspect the coils and icm terminals for corrosion when you were there? that can cause the same kind of issues.

mrpontiac, that sounds a lot like what I'm dealing with. Do you still have the problem even after replacing your Cv-joint?