i will have to disagree. had my prochamber with dallas mustang mil's and light kept coming on & going off for about 6 mo. or more. finally, i got sick of it & when i got chip, it went off for good. i think it made my car run a little worse, can't explain or prove it though; so ??? just seemed kinda sluggish. not that it hurts anything; but after awhile, maybe that light starts getting into your head i think. mostly i just got tired of explaining to everyone who got in the car why it was on. everyone will tell u that its on; like u had never noticed it b4.