Celica Forums General Discussion Engine and Performance Need advice on my engine.

I own a 2000 Celica and my engine has been sort of pulsating/vibrating really hard. It happens when I start the car and the rpm is between 1 and 0 or closest to 0 but when I give it a little gas then it goes away and doesn't return until I turn the car off and back on a few hours later or the next day. It also vibrates when I go in reverse, only when I first start the car though. I'd usually let the pulsating/vibrating go away on it's own but last time I did, the car stalled on me. I've taken it to a few mechanics but they've told me that everything looks fine, except I have a minor oil leak in my engine. I think I may need a new oxygen sensor but I'm not sure. I've also noticed a loss of power sometimes and low fuel economy. If anyone has any thoughts or comments on what may be causing this problem please let me know. As a side note, I got a new catalytic converter a couple months ago, had a tune-up when I first got the car (last September), installed new ignition packs/coils in March, and got a new fuel tank last Thursday.

If engine runs rough at idle speed, then smooth out at high RPM, the cause is usually a dirty or broken Mass Airflow Sensor. The MAF may look and test OK, but the Platinum sensor element may be dirty or damaged.

A quick test is to swap in a known-good MAF. All Toyota and Lexus sedan use the same DENSO MAF sensor. It's on top of the main air hose, right after the air box, into the throttle body. Remove 1 connector and 2 screws.

Put it in your car, reset the ECU by removing the battery's negative terminal for 5 minutes. Then restart the car and drive around for the ECU to remap the fuel trim.