2004 gmc envoy_slt
Very weird problem, I noticed it as soon as i bought the vehicle 04 envoy slt, only headlights will dim every so often(very quick), sometimes it will do it back to back then no problems. I have also noticed my check engine light comes on all the time then will go away, about a week ago my check 4wd light came on then went off when i drove for while turned key off then back on. I thought the check engine light was just bad gas cap but cap seals fine. i've seen plenty of posts where the lights dim but there's seem to happen more often then mine. Anyone have any idea?