i heard a 01 that was idled up and loved so today i found out how too. not hard just turn a screw a couple of times. anyways after cranking the car bout 4 or 5 times while i was going down the road the check engine light came on. it idles at about 2 grand and drops to bout 1100 after 7 -10 secs. also when letting off the gas while coming to a stop the rpms go back and forth from 1100 to 1900 then eventually stops at 1900-2000. can anything go wrong?is it hurting anything?