1990 350 tpi. Okay well i bought my camero about a month ago and when i first had it on the road if i got over 3500-4000 rpms id get this massive vibration. At first it seemed like it was coming from infront of the dash....then it seemed more localized to from near the transmission like right beside my right leg but you can feel it through the shifter ****. My friend also said when he sat in the back he could feel the vibration too so ive had a tough time pin pointing it. The sort of vibration was similar to something turning over ie drive shaft it was like you get the heavy vibration for a half second and then off for a split second back on for a half second off for a split so the sort of vibration from something turning over (if you dont understand ill try to explain better)....the tranny mount bushing is still there and i replaced the u joints but that had no effect. Now the problem has gotten much worse to the point where i get the vibration during all acceleration and deceleration. Its really weird because it seems fine at first but as the car warms up it gets worse and worse and worse until the point where it becomes totally undriveable.

I took it to my mechanic and he took just a quick look at it and told me i wasnt getting the proper current coming off the alternator and that this would effect my computer and how it operates potentially causing the vibrations. Heres a couple of things.....one doesnt the computer just pull from the battery so even if the alternator isnt working at 100% shouldnt my battery just drain slowly i wouldnt think this could effect my computer. Second any way in hell the computer could cause this sort of problem because i really doubt it. Third my mechanic has been for a ride in it and knows what the problem feels like and im 99% sure it has to be drive train related.
Any chance it could be because of the alt.?

If youre still reading this thank you. Anyone have anything to check possibly towards the rear end of the car? i also hear a slight whirring coming out of the rear end but i think it just needs new gear lube. Any tips for things to check i am greatful for im at a loss and think my mechanic is a crazy man so hes not much help.

 

your drive shaft could be off balanced or hitting the exhaust mine was hitting the exhaust i could actually feel it in my gas pedal

 

no its definitly not hitting the exhaust and there is no noticeable vibration in any of the pedals. Im going to take it soon to get everything balanced/aligned and see if that does anything.

 

My guess would be to replace the u-joints. That's what it sounds like to me. I wouldn't think the exhaust bouncing off the drive shaft would cause the much of a vibration....although I could be wrong. I've only experienced that once....In an 83 Blazer. If you change the u-joints and it doesn't fix it, you're out 20 or 30 bucks...Big deal. Anyway...just my two cents....Good Luck!

 

i mentioned that but its kind of buried in the middle there....i have replaced the u joints but it did nothing. I am losing respect for my mechanic by the second and want my car back in my own hands asap. I havent taken it to an alignment shop since i bought it so im going to do that. Im going to have all of the tire balances checked drive shaft balance checked and all of that.

Something i mentioned is i noticed a slight whirring noise coming out of the rear end. Its only at part throttle but ive been told this could be the sound of my rear end going. I have to swap the gear lube thats in there anyways how can i check to see if my rear end is going?

I was also wondering is headers/shift kit/3.73 gears enough to fry a 10 bolt? i doubt it but i thought id check.

 

How could it be the drive shaft or rear end of the problems arise around a certain RPM, and not speed?

You said around 4k rpms. What if you are going down the highway at 60mph but turning 2k rpms? Problem still there?

 

see thats whats throwing me that i cant figure out. Okay heres the cenario. If everything on the car is cold lets say its sat for 24 hours i can start it up and start driving no problems anything. If i get on the gas hard i feel it at higher rpms. However if ive been driving for even 2-3 minutes you start to feel it at anything over 50 kilometers and i feel it under breaking too. I cant figure out for the life of me what it is.

 

One thing I would not recommend is 3.73s...especially with the A4 tranny. As you probably know, TPI runs out of breath around 4800 rpms. Putting 3.73s will make your car rev out much faster and make your car come out of the powerband if you're accelerating all out. But then again...what do I know, I'm just a stupid 16 year old.

 

does it vibrate when the car is warm and not moving? like in park and you rev it up

 

rofl thanx man but i really dont care right now. All im concerned with at the moment is getting this stupid thing working.

Thats actually a really good question and im not sure. I dont get the car back from the mechanics until tommorow but when i do ill check that. That will at least let me localize it away from the engine/tranny.

Note: i just thought id add that i didnt put in the 3.73's they were already in when i bought the car but i love them. Not sure what it does to my 1/4 mile times but it makes the car absolutly haul when you hammer it from a light in the city. Although if i had a choice id probably step it down to some 3.43's or something but having them in is definitly not a bad thing.

 

Have you checked to see if you have any warped brake components? Another guess would be a broken flexplate...

 

wouldnt be the brakes. Could possibly be something to do tranny wise ie flex plate. I have to find a way to localize this problem to either by my tranny or by my rear end hopefully ill be able to so i can pin point the problem.

 

Easy way to pinpoint: hold it in first and drive it up to about 4500rpm.....if you don't get the vibration then its not engine related.

 

but if its solely rpm related if i drive it up to 4500 in 1st ill still get the vibration....the neutral idea seems better to me because in first i have the engine and drive train spinning so i cant pin point it. In neutral only the engine is running.....i think im right, please correct me if im not.

 

You are correct but it's also very possible that the vibration won't show up unless the engine is under a load. I see cases like that at work all the time (they usually turn out to be ignition related.)