AlwaysCode390

My EGR valve code p0400 has been on for awhile. I decided to swap the valve out with a new one, and the code came back.

From reading threads on here, it is probably from my headers and free flowing mufflers ( no backpressure ).

If I get ION to tune out the code, the egr is still functioning....but the code wont show, RIGHT?! How about when I go to get emissions tested....will the egr show "not ready" or will it pass???

If I decided to just block off the egr one day....will the performance of the car increase/decrease/ or just stay the same and be stinkier out the exhaust ( unburnt fuel )???

Also my car was idling at around 950rpm in neutral ( m6 ) before I swapped it for a new one... is my tach just off or does it idle high if the egr is blocked??? I was telling someone my rpm at 60 and they thought I had 3.73's installed but they are stock. Please let me know, thanks alot ---

Severous01

did you reuse the gaskets or did you replace them? it could be leaking air in and just like the 02 sensors it'll throw a code.

also, check for hairline cracks in all the vacuum connectors. if you need, advance sells kits to replace all the vacuum lines and connectors.

JimboManJones

The code won't show. If ION tunes out the code, egr won't work. The egr will show not ready. To get it to show ready read here(read the whole thread)

http://web.camaross.com/forums/showthread.php?t=366280

Exhaust smell won't change unless you delete cats, performance of the car will stay the same, unless you dont do a good job blocking it off and get a vaccum leak.

And your tach is probably off, mine is off by 200 rpms(confirmed by scanner) at idle. http://www.f-body.org/gears is a good gear/mph calculator to check and see what gears you have, plus its cool to play around with.

2000GTP

What kind of aftermarket exhaust do you have? When I did long tubes, off-road y-pipe, and a catback, I got the same code. From my understanding, there is not enough backpressure to properly operate the EGR system. If you have the EGR completely deleted from your PCM, it will post a "not ready" status and it can effect you passing. However, Ion CAN tune it to be compliant and work and not post a "not ready" status. He did this for me and I passed emissions with no problem.

AlwaysCode390

Exactly what I wanted to hear. I have a set of edelbrock shorties, an offroad y pipe, single cat, and a flowmaster catback. When I let off the gas at ANY RPM it pops out the exhaust alot ( NO BACKPRESSURE ). I will recheck for vacuum leaks and then decide to tune it out completely or just the SES light, THANKS ---