Hi. I have a 2008 V6 4runner with just over 100k miles. I recently notice that the idle when at a stop light (in drive) will suddenly drop to just over 500 rpm from about 800. This creates a really low rumbling sound, which I initially thought was a big semi stopped next to me until I noticed it at other stops. After a few seconds, maybe 10-15 it will bump back up and smooth out. If I feather the throttle, it is smooth as can be around 800 rpms, but if I let off the pedal, it will fluctuate back and forth from smooth to roughish and annoyingly loud and low.
I read all about cleaning the throttle body and MAF sensor, but people seem to do that for other reasons like throttle response or mileage. Both are fine with mine and it idles great when in park. Can anyone help me figure out where to start. I just would like the idle to stay in the smoother range. Also turning on AC, fan, etc. has zero impact one way or the other.
I'd appreciate any input.
I read all about cleaning the throttle body and MAF sensor, but people seem to do that for other reasons like throttle response or mileage. Both are fine with mine and it idles great when in park. Can anyone help me figure out where to start. I just would like the idle to stay in the smoother range. Also turning on AC, fan, etc. has zero impact one way or the other.
I'd appreciate any input.
