Has anyone experienced their rpm's reving on a cold starts it automatically revs up and down...... up and down......since i have an exhaust it sounds weird.......but the rev is only 1.5 and slowly goes down from there. I'm just wondering if this normal operation or something will give out on me sooner or later?

Thanks.

 

It's "catalytic warm up" and is 100% normal.

Should not be "revving" btw, just starting at 1.2 - 1.5 and mellowing out as the cat temps rise. If indeed it's "revving" 800 - 1500 rpm repeatedly then take it in. Your maf may be the culpret.

 

yup, just one of the quirks of our cars, nothing to worry about.