I searched for a long time before I decided to post this. I found a bunch of threads about shaking during acceleration or braking, but that's not quite what I'm seeing on my wife's car. (1999 2.3L, 120,000 mi)

Problem:

I noticed this when it last week....I was driving at a constant speed of about 40 mph and then all of a sudden the car started to shake (seemed to come from the front left??). My rpm's were normal and not fluctuating, dipping, or spiking. I took my foot off the gas and put it back on the gas to continue at that speed and the shake went away for awhile. Then several minutes later it came back and the same process made it go away (remove foot from gas, replace foot on gas). This is not during any acceleration or deceleration, it is at a constant speed. My father-in-law has suspected the motor mounts, but I would think it would be more constant if it was a motor mount. What do you guys think? Thanks a bunch!

Sam

 

sounds like it might be an unbalanced wheel (though it will usually shake between 50-60mph).
if youre due for an oil change or whatever, might want to have them rotate and balance your wheels while youre there

 

If it were a motor mount, it would be all the time, increasing with rev'ing. I would guess your alignment, a wheel bearing, or a bent wheel?

 

I will have the wheels checked out very soon, we are coming up on needing new tires. I don't think it's a wheel though since it goes away when I left off the gas and then put my foot right back on. I also noticed last night it goes away if (before letting off the gas) I push on the gas more causing the transmission to downshift.....could it be an axle or CV joint? Thanks for the replies so far guys!

Sam

 

Most likely it can be your axle I had the same problem for about a yr, the dealer nor a local mechanic weren't able to determine the problem, I basically went out and bought 2 new axles, guess what man?, problem solved! after a long yr of torture, a suspension shop can check them out for you , let me know how it goes

 

Axle/CV boots are a possibility, but its most likely a bent rim. Ask her if she has hit any pot holes or small children recently... 3 of my wheels are bent and have the same vibration, but it is usually only noticeable at 60+ mph.

 

I'll take a closer look at the axles and joints this weekend. She says she hasn't hit anything major, and she usually calls me as soon as she does something that could even remotely damage the car (scared of hurting it maybe?). I'll definitely have the wheels checked when I put new tires on, in fact I may rotate them this weekend just to see if anything changes. Thanks again for the replies guys!

Sam