[j.fro]

I used my Durametric software and with a bit of advice from a local mechanic was able to solve my MAF issue.
Waaaaay back in '07 I had a MAF CEL, so I decided to update from the original 124 MAF to the 125.01 MAF. I haad an Indy do the ECU update, but they said something odd had happened but they couldn't explain. Hmmm... Nevertheless, the car ran with the new 125.01 MAF and my CEL was gone.
a year or so later, on a dyno test, they said I was running lean. Hmmm....
Chased the problem for a while, but no CELS so no worries, right?? not really.
I posed the problem to a different local mechanic, and he said he thought I had an MAF issue. OK. So I pulled the 125.01 from the car and put my old 124 in (I dont throw anything away). At idle, my O2 sensors showed 0.85.... rich, but a long way from the lean 0.045. But the car wouldn't drive. On acceleration, the car stumbled and coughed. Bad MAF. I looked at the MAF in my '99 996 and sure enough it was also a 124. I put it into the Boxster and holy **************** the car runs great. Great drivability, great numbers. I used Dash Command to monitor the 02 sensors while I drove around a bit, and they happily bounced between 0.2 and 0.8. Right where I want them. I put that MAF back into the 996 where it belongs and found another 124 on eBay. That went in, and the car is running better than ever. Off the line it is ON, and the mid range is much better than before. O2 numbers are right where I want them. I'll be scheduling another dyno test soon to see exactly where I am.
Bottom line. If you've got an older car and are updating from a 124 MAF to 125.01, make sure they do the ECU right. Or stick with he 124.