Vibration at 3000 R.P.M.

[Goombatz]

My engine would vibrate pretty bad about 3k RPM - especially on the freeway - about 70 MPH. I decided to change the front motor mount myself (with the help of all these wonderful people from Renntech.org). :renntech: Changing the mount made such a difference, my Boxster was fun to drive again (2001, 2.7L, 5 speed, conv. 70k mi.)

About 1k miles later, the vibration started up again, it wasn't too bad but the engine was running rough at all speeds. I replaced the spark plugs and installed new ignition coils, this made such a difference! Not only was the engine running smooth, I also felt like I regained a few horsepower!

2 months later the engine vibration started up again - this time it felt really rough, the whole car was vibrating around 3k rpm. I thought it was from installing a crappy engine mount - either i didn't tighten everything up good or maybe it was a defective mount. At this point, I was thinking about selling my car because she was running too rough, she needed new tires, and I was starting to believe her age finally caught up with her. So I bought 4 new Hankook EVO tires (on 17" rims), had them balanced and 4-wheel alignment. Now my car rides like a dream - so smooth, stable and handles great!

I had no idea really worn out tires would make a car feel like crap. I really milked those tires - very bald on the inside. It's possible I may have lost a wheel weight too.