Copilot

Hopefully this thread will help document a successful resolution. We'll see!

If you look up some of my other threads, you'll see I had to have my heads rebuilt last summer - in the process, replaced a bunch of parts, seals, etc.
I also did a number of performance upgrades - IPD Competition Plenum, GT3 throttle body, 997 headers and put on a new Top Gear catted X-pipe. All work/mods were done about under 1000 miles ago.

Driving the car about a month ago, got a CEL. Drove home, hooked up the Durametric, and pulled a P1109, 0420 and 0430. I figured, ok, probably a MAF issue (I used to have a K&N Cold air intake on the car), so I cleaned the MAF. Drove about 50 miles, and the codes came back. Hmm. Okay, so maybe the MAF is bad? So I bought a new MAF. Put it on, this time drove it for about a week and probably about 200 miles... and the codes are back again!

Any ideas where to troubleshoot next? For reference, the GT3 throttle body I used was brand new, so I really hope the throttle body isn't the issue. I have to figure the 0420/0430 codes are resultant from the 1109 code... if not, I'll have to send a quick email to Topgear letting them know my new cats aren't functioning properly.

Ahsai

A few questions that might help.
1) Have you tried e-gas calibration?
2) What's your MAF voltage (read from Duramectric) when you turn the key to the last position before cranking?
3) What's your MAF voltage (and mass air flow in kg/hr) at idle with fully warmed up engine? (no load such as a/c)
4) At idle, fully warmed up (no load) on both banks, does the precat O2 sensor voltage swing between 0.2v to 0.7v about once a second? Does the postcat voltage stay more of less at ~0.7v?
5) What are the RKAT and FRA values on both banks?

Copilot

I'm embarrassed to admit I forgot about the e-gas calibration. I remembered looking up DME reset info after I finished up the work, but left it at that. I'm going to give it a shot and see how it goes. I'll play around tomorrow and get the rest of the numbers too.