The check engine light came on today. I got it last night. It has a new motor and transmission with a bout 30000 on both. I can't see or hear and thing that would be wrong. The speedometer doesn't work(didn't when I bought it) could the speedometer cable be what's making g the CE light come on. Its also Makes a rattling noise. Its not engine problems. Atleast I don't think it is. It doesn't do it all the time and sometimes just at certain revs and sometimes while idling. More at higher revs. It sounds like it could be a hanger on my exhaust somewhere I'm not sure but its bugging the hell outa me. Any Information or advice is really appreciated. Ill try to post a video tonight. Thanks.