Strange Shudder

[Sonicxtacy02]

Anyone wanna gimme some ideas on what can cause the front end to vibrate/shudder when cold but stop when hot? I was thinking its a problem with the motor mounts but why would the problem go away at NOT?

[dylanmx3]

A few things are different when your engine is cold...idle speed is one major factor, your mount temp is another. I'm not sure how cold the "cold" is that you're refering to but here in Canada, this time of year, your mounts will be hard as rock. If your mounts are worn or you've changed them (filled the voids) you will likely get more vibration transmitted through them. As your engine warms up the idle drops and you can be getting away from a resonant frequency found at higher rpms. Quick check...once your engine warms up slowly bring your rpms up...everything has a natural frequency...when your engine speed matches that frequency you'll get a vibration...a classic is the exhaust system...mine lights up at about 2400rpm...just when it's cold. It's kinda like the tire out of balance vibration happening around 110kph to 120 on most cars and around 140kph in the MX3 (stiff suspension + light wheels = higher freq).<BR>Let me know what you think<BR>Dylan

[killerpickle]

I believe a poor air fuel mixture can also cause rough idle. Which is what I experience right now with my faulty o2 sensors. I goes away once the engine reaches operating temp (around 930 on the temp guage)<BR>my car also shakes bad when its really cold.<p>[ December 11, 2002: Message edited by: killerpickle ]

[your2slow]

I"ve got a 1996 MX-3 GS and mine is silent in the cold or heat. I can even bearly tell the my car is on when i first start it. I also live in Canada and it can get really cold here but never had an issue like you guys. What could be the reason?