Recently my car has been acting up while at idle. It doesn't consistently happen, but while at idle my car will randomly shake as if it is misfiring. It will do it for a couple seconds, then it stops.

It seems to drive normally, I'm not seeing any difference in performance other than my gas MPG seems to be getting progressively worse since the issue started earlier this week. This rumbling issue only happens when I'm not driving and I'm sitting still.

I changed the valve cover gaskets about 6 months ago, so I don't think it is an issue with my spark plugs being affected by oil getting into it. I also just cleaned my MAF sensors and throttle bodies assuming that it would fix the issue, but it did not work.

My car also smells like it is running rich. My car is tuned, but it's to the point where I can smell it from outside of the car after starting the engine. While at idle, my car randomly backfired as well. I have looked at other posts but I can't seem to pinpoint the issue.

What should I check next after cleaning the MAF sensors and the throttle bodies? Any help is greatly appreciated