My car shakes violently when I come to a stop light. The shaking stops if I put it in neutral or park. Ruled out motor mount, air control value, brake roaders.
It sounds like it’s just plain idling rough. Has the check engine light come on? My offhand guess would be a dirty throttle body.
Does it only happen when applying the brakes? Bad vacuum hose or booster would be a possibility if applicable.
Misfiring. First step check for diagnostic codes.
There are no diagnostic codes. Thanks for the suggestions. I will let you know what I find.
This implies that the transmission is causing excess drag on the engine.
And the engine isn’t compensating. Since the OP ruled out the idle air control valve and there are no codes I still suspect a dirty throttle body.
Could be. That would prevent enough air from getting in - and the computer would cut back on the fuel - and it would lose RPM, stumble, maybe quit running. But wouldn’t the IAC valve take action to overcome this?
You’d think so but beats me. Something is making the engine run rough and throttle body is my best guess. Could be a vacuum leak too but whatever it is it would be nice if there were a code.