Hi. I recently purchased an automatic 2008 Toyota Matrix with 220,000 miles that's in pretty good shape. When I'm waiting at a light with the car in drive, it really idles roughly, enough to shake me pretty good. It still shakes some while I have it in park with the engine on but far more when in drive and foot on the brake.
It runs OK when I'm moving. I just filled it up for the first time and I only got 20 mpg in a car that should do at least 26 to 32 according to most drivers. (fuelly.com)
I thought it might be a motor mount but the guy at firestone did this test of pushing the accelerator with the car turned on and in park. The motor did not move so he said it's not a motor mount.
What could this be?
Your torque converter may be faulty. About the mpg, start with cleaning the MAF sensor, throttle body and change your engine air filter.
Is your check engine light on? If not does it light up when you turn the key before you start the car?
Thumpy, the check engine light is not on. It does light up when I turn the key to the ON position and to start the car.
Sorry for the late reply. I didn't get notification of another reply!
With 220,000 miles, I suspect you probably have low or unequal compression in the cylinders. Have it checked to see if it can be eliminated from the diagnostic process.
Never hurts to clean your idle air control while doing the maf and throttle body.
