Light Vibration Before Engine Warms Up

[wandawoods]

hi guys,

for my 96 SC4 /169k, some light vibration has developed about a month ago.

I usually don't really warm up car at my driveway, I just startup, wait about 15~20 seconds then go. however, recently when step on gas, even lightly, I can feel some vibration till engine warm up to normal range (slightly below mid point at temp gauge). as soon as it warms up, the vibration will be gone.

this happens at low speed as well as high speed, and it's very hard to determine where it comes from.

engine oil is Mobile1 full-syc 10w-30 (for high-milleage) and recently changed. brakes, struts are all new. I don't think is tire (under 3K-miles new!) balancing or alignment problems because the vibration goes off at any speed once engine warms up.

could it be motor/tranny mount? but that won't explain why vibration is gone after reaching operating temp!?

TB/water pump was replaced at 125K, drive belt & couple of pulleys was just changed few weeks ago.

cound it be tranny itself? just done the pan drain-n-fill with type T-IV, but have not done the full flush. will that help?

any comments is welcome and appreciated!

[jeremyp]

Can you feel the vibration while reving the engine while it's in park or only while moving? If you can feel it while in Park then it could be a tranny or engine mount. If you only feel it while driving then it could be tires, mounts, driveline, etc. I had a tranny mount that was so bad it made it feel like the engine was out of balance.

[jzz30]

had the same symptoms on both of my cars and tranny mount was the culprit. you might as well change the engine mounts too and your car will run as smooth as new.