In episode 7 of the 1A Auto Talk & Tune, Dan was unable to participate and was replaced with a clock. Jeremy then attempted to answer 15 viewer questions in 10 minutes, and fails terribly.
If your car or truck is experiencing idle problems then this is one thing you could check for. Carbon buildup in the engine throttle Body can restrict air flow. This will cause the engine to stumble as the engine reduces speed. As the idle decreases the engine will be "choked" for air due to the carbon build up so the engine changes the mixture temporarily to make up for the restricted air, the idle raises back up then starts to let itself down to idle and the process repeats.
If you have a check engine light code P0420 or P0430 there may be a problem with your catalytic converter. But sometimes, the problem could be the oxygen sensor that takes readings from the catalyst. Watch this video to find out the difference