Hi i have a 2009 corolla le with 220000 miles I have had a vibration issue since November ive taken to multiple mechanics. I have changed a engine mount new spark plugs throttle body clean engine flush mass air flow sensor air filter oil change and a few others recently took to toyota dealership for full diagnosis and they couldn't say what was wrong since no check engine light. They suggested fuel clea... Yesterday i noticed when my headlights are on they car does not vibrate ...any ideas on what could be wrong
check your battery, alternator and serpentine belt.. they all work in unison to maintain your idle smooth as your ECU sends the data in from the MAF readings. if any 3 of those things are off, then it will cause a rough idle.
I had a bad idle at a stop but once i replaced my battery i was all good, another time my serpentine belt was bad causing a similar issue and replacing it helped me as well, also- if any 1 of those 3 is bad, it will negatively affect the other 2 as they all work together.
if you haven't run seafoam through the car's throttle body and fuel system together, DO IT! (SS14 Throttle Body Cleaner + SF16 Fuel Injector Cleaner Additive)
it'll help clean your carbon buildup, and the seafoam fuel cleaner will help with cleaning fuel injectors. also, ensure your fuel injectors are clean, there's vidoes on youtube on how to clean them, they may be gunked up and need a cleaning, or you may need to replace them.