luckythirteen13

mstng67 that could be. my check engine light is doing exactly what you said yours is doing. i checked my codes and it came up with egr valve so i have to get a new one before smog but sense thats not for a few months im in no hurry.

where is the best place to get a new egr valve?

Djs94stang

If it gets stuck closed you also may notice part throttle detonation since the spent exhaust gases cool the combustion process...that's how the NOX is lowered....by cooling the combustion temp