CEL keeps coming back !!!
 

2001 Boxster S (manual 6spd) Installed all new Bosch O2 sensors. Car runs good. After less that 90 miles...CEL back on. Codes P1126, P1133 always keep showing up. First new code is P0102..MAF sensor...never on before now. MAF shows erratic patterns on Durametric test grid. Don't want to 'throw parts' at it. Any thoughts ???? Thanks

Classic MAF failure.
Is it sluggish when you get on the throttle hard?
You can try cleaning it, but it may need to be replaced.

Make sure you buy the correct MAF.There are 2 different ones - old & new. Yours is late enough (IIRC) to run the later version w/o a DME flash. If you buy using your VIN to get the correct part # ,from a reputable source ,you will get the correct one. If you do not use your VIN .....

P1126 and P1133 mean that the car is running lean and has trimmed rich to it's limit. This could be a failed MAF or an intake air leak. Lots of info in these forums if you run a search on these codes. When I got them I disconnected the MAF and the car ran better. I replaced the MAF and it solved the problem. In some cases it is a rotted vacuum line, loose intake connectors or someone was tinkering with the plenum and failed to get things all buttoned down again.

Process of elimination first, then buy parts if still needed.

Try disconnecting the MAF and go drive the car. If it runs noticeably better replace the MAF. If it runs noticeably worse, start looking for an intake air leak.