Hi scotty how are you? I have a check engine light on my 2007 buick lucerne with the 3.8 liter v6 and it says emmissions control circuit. I just cleaned the egr valve, throttle cleaning and maf cleaning. Also my transmission clunks at heavy throttle applications, shifts excellent. Is it my mounts? Also what about spark plug gap. I always use iridium spark plugs. I was thinking of altering the gap. For better mpg.
Oh boy. Thank you soo much scotty! Your a life saver!
do not alter the gap, period. Emissions are complex , so find a guy with a dealer scan tool to analyze the system, or heck, try a new gas cap first. Pray your cv joints or motor mounts are making that noise, and not the transmission itself which it often is on that model, sadly.