Mattarbour

I have a 1989 Mustang Cobra with bad vibration at 3000 RPMs. I have some idea but not sure. Hopfully someone on here will save me some time and money. Info on problem and car below.

1. Vibration Starts at 3000RPMS

2. Does not matter what gear im in Neutral, 1st, 2nd, 3rd, 4th, 5th the vibration is always there.

3. Cobra has Headers, GT40 Heads, 25lb injectors, Pullys and more.

4. I had the Harmonic Balancer replaced and motor mounts are good.

5. Engine is a 302 H.O. from a 1991 Stang

My Ideas:

1. Clutch needs to be replaced
2. Flywheel needs to be replaced
3. Both

Anyone have any idea's or maybe sombody had the same problem? Please Help i am running out of ideas and spending a lot of money.

Thanks in advance,

Matt

nseoi

first off for it to be a cobra it has to be a 1993, so its gotta be a clone or a canadian GT

i would have thought it was the harmonic balancer but thats been replaced :/
someone else will chime in with something more helpfull im sure

stang8689

Could be a driveshaft weight that fell off

vmpetrone

You may want to check your fan clutch and water pump to make sure that nothing is loose. I would forget about the drive shaft weight because this is an RPM issue not a speed issue. The only thing that I dont know is if it still has the vibration when your sitting still with the clutch pushed in. That would help to rule out the transmission completely.

Mattarbour

Well I can Rule our the Clutch Fan already tried that and water pump is good. I am getting a new 50oz flywheel and clutch installed on Tuesday hopfully that takes care of it. I never thought of putting in the clutch and gasing it to see if it still vibrates. I will check. What are you getting at if it does or does not? I would think it does still vibratebecause if your in neutral it will still vibrate. I'm thinking the flywheel is worped or not balanced.

One thing to add the drive shaft had a fair amount of play in it when i put it on a hoist. Its tighned back up now but maybe that can give some indication on what it might be????

Thank you for the suggestions keep them coming. I will keep reporting back on what i find out. so someone with the same problem can seesome answers.

vmpetrone

With the clutch pressed in the main shaft in the transmission will not turn. If it is in neutral without pressing the clutch the main shaft will still turn. If you rev it up in neutral while not moving with the clutch pushed in you can narrow down the problem to the engine and flywheel/clutch.

5.0 steve

driveshaft weight that fell off happend to me 2 months ago buy the weights there cheap,putem on takes 5 min

Mattarbour

I found out..... It was the Flywheel. Thanks for the suggestions everyone.