so after i ran some "engine cleaner" stuff through my car, my engine has started chuggin' when it's idle and warm it'll be around 700rpm then drops down to 600 rapidly for a few second and sounds like it's gonna die... anyway, i suspected it was my fuel filter, so i changed that. i checked spark plugs, they're fine, i don't know what it is, plz help

 

try adjusting your the flat head screw on top of your throttle body to fix the abnormal idel... the clunking... wheres it coming from? is it like a mild ticking type sound? Might need to have your valves adjusted again.