Flat_Tire_

Here's the story ...

Had a 232/232 112LSA cam installed along with new valvesprings, retainers, and pushrods. Got it tuned. Dyno numbers were much lower than expected. SES light came on and eventually went away before I had a chance to scan it. So I picked up an LS6 intake (no EGR), ported throttle body and Magnaflow cat-back (used to be a custom catback w/ flowmaster muffer) and had them installed. Had the car retuned, dyno numbers were a bit better but still seem REALLY low (375rwhp, 357 rwtq). Picked it up and on the drive home SES came on again, scanned the car that night and I had TWO p0404's and one p0121. This is how my car sits right now. I've been waiting a few weeks to get some new fuel injectors installed (current ones are maxing out in the upper RPM's) and my SES light has been on the entire time. Tonight, just to checkup on things, I rescanned and pulled P0404, P0135, P0404, P0155.

I delete the codes. Go for a drive, 20 minutes city streets, no SES light. I get on the freeway. SES light comes on ~30 seconds (I counted) after I engaged 6th gear, 70mph @ 1900 RPM's. ... I counted this time because the first time the SES light came on I noticed it was immediately after getting into 6th gear .. And i've been driving the car in 5th cruising since then, except for tonight to see what would happen. I scanned the codes immediately after they showed up, and it shows P0404, P0153, P0404. 153 is not a typo .. 153 = slow response from 02 sensor bank x (froget which bank) sensor 1, and 155 = 02 sensor heater circuit failure bank x sensor 1.

I again pull off the road. Delete the codes. I begin driving again, city streets, never went into 5th or 6th gear. I get dinner. 30 minutes later I drive again, 10 minutes city streets, get on the freeway. Cruise at 70 mph in 5th for 15 minutes. I stick it in 6th and 30 seconds later SES light and p0404, p0404.

So what's the deal? Something is hinky and casuing two p0404 codes to be thrown at the same time. I realize that p0404 = EGR failure, however the tuner tuned it out during the 2nd tune and if the problem was in fact EGR, I would think it would come on a lot sooner and not be triggered by me doin 1900 rpms in 6th gear. I realize that 1900 rpms is outside the powerband of my car, but should that prevent me from cruising below that rpm range? And why the hell would it trigger 2 p0404 codes. Is it possible that the scanner I'm using is trying to read a code outside of its input range so it ends up reading 2?

Thanks for your time. I apologize for the extremely long post but I don't think I could have explained my situation more clearly without doing so.

AL SS590 M6

I would guess that the tuner didn't get all of the EGR stuff eliminated from the 'puter. Low rpms in high gear is when EGR is commanded on.

For the O2 codes check the routing of the wiring. Could be getting hot.

Flat_Tire_

Ohhhhh, ok. I had thought it just ran a routine test .. Thanks for clearin that up. And yeah I gotta get underneath the car and checkout what's going on with my O2's. They seem too be throwing codes when they're cold though.

AL SS590 M6

The comp does run an EGR test upon entering closed loop I believe (maybe at start up). But the function of the EGR is during cruising.