Vibration from 3800 to 4500 RPMs

[allezgrand]

I am having really bad vibration in the engine between 3800 and 4500 RPMs and it sounds like crap as well. It is a 91 TSi and it does it regardless of whether or not there is a load on the engine. I have new plugs and wires and coil pack. I am 99% sure that there is no problem with the balance shaft alignment either. New capacitors in the ECU and all 60k mile maintenance done. Performance does not change through that curve. The car only has 60k miles on it. I can't figure this out. Need some help.

 

[allezgrand]

I apologize if this was the wrong place to post this. I didn't read the rules until after posting, which I know I should have done first. I do have significant experience with this car, but I have not (yet) done a complete rebuild nor am I making over 400hp. I am running a big 16g, but have very few other mods since I have spent all my money fixing problem after problem with this car.

 

[thekellbeast]

Posting in the wrong forum isn't THAT big of a deal - this isn't NABR. :laugh: Just report it to the mods and ask them to move it. Sorry I can't help you with your problem though.

 

[pneumo]

I had the same vibration when the front balance shaft belt broke on my car. Did the balance shaft belt get replaced during the 60k mile service? Many times they're not.

It might also be a torn motor mount.

 

[allezgrand]

Yeah, I replaced the balance shaft belt. I will check about the motor mount. Thanks. When you had the vibration from the snapped balance shaft belt, wasn't it a vibration all the time though or did it only occur in this RPM range for some reason?