Where do I go from here?

[Chappy1062]

I knew there would be a learning curve and that it's always a gamble when you buy used. In the three weeks that I've owned this 08 coupe with 33K miles, I've over come a clearance problem with the exhaust and the constant bumping in tunnel after it heated up (thanks Top Gun in FWB). I was not provided any information from the previous owner so I learned that it has PFADT headers, high flow cats, X-pipes, dual mode exhaust with Mild to Wild installed, and Halltech cold air induction system. I'm not sure if the Halltech is a 103 or 108 but it has the 4.5" inch filter. No other distinguishing markings on the tube that I could find. Three days after I purchase it set engine codes PO455 evaporative emissions system leak detected gross leak / no. Changed the gas cap for this. It also set PO420 catalyst system efficiency below threshold bank one confirmed (cats looks good). With the mods this car has I have to believe that it has a tune but I'm not sure. My question is should I look into having someone read the current tune, get a "new tune", or are there any other maintenance area(s) I should be looking into? Recommendation/Advice?

 

[Rich Z]

In a lot of cases, headers will move the O2 sensors and/or the catalytic converters, and that can often trigger error codes related to those components. Because of this many tuners will just disable the error trapping codes. Heck, you might want to put your car up on a lift and eyeball everything. I had one shop splice in trailer hitch and radio shack wiring into my O2 sensor harnesses when they were working on my C5Z. And the guy wondered why he was getting all kinds of odd error codes showing up.

As for the "PO455" error, seems to me this can be related to a filter cannister that on the C5 is located on top of the passenger side gas tank. It's purpose, I believe, is to capture gasoline fumes from the gas tanks. There is a bunch of associated plumbing that could come loose, I suppose, or even vacuum hoses that can come loose or develop holes. But I had nearly all that stuff either removed or disconnected, and disabled the error codes on the whole mess. There was a pump of some sort behind the front bumper fascia that if I recall correctly, is supposed to trigger periodically to flush the canister mentioned above. And yes, a bad or loose gas cap can trigger that error code. So if your replacing the gas cap cured that one, count yourself lucky.