If you read the forums enough, the answer is there.

[dickgeorge]

Bought a 2001 Boxster at Park Place LTD, Redmond, WA. As I was testing it, the CEL came on, so sale was contingent on fixing the issue. They installed MAF and light was out. I picked it up, and 20 miles later, light came on. They are really great, high end auto sales (Ferrari, Porsche, Ford GT, Superformance, Bentley, Aston Martin --- nothing but high end) and offered to supply a car while it was being serviced. On the way to drop it off, CEL went out and no codes available. I took the car back and drove it for 3 weeks and the light came back on (P1126, P1133). I pulled the data with my notebook PC, printed it and took it with me. All the data indicated a slow O2 sensor. Graphs, carts, data, everything indicated that an O2 should be changed. Light went out again on the way to service. I gave them all the printouts, and it was just what this site indicated -- AOS bellows. They replaced the AOS and the bellows and the car is just fantastic. After they repaired it, I took another look at the O2 data, and it was perfectly normal. Today, I pulled the throttle body and sure enough, dirty and accumulated crud and blocking most of the opening at idle. Cleaned it following the DIY guide I found here.

Bottom line. If it had not been all covered work by Park Place and I had to find the problem myself, if you read the forums carefully, the cure is there.

Glad I found this forum. Thanks everyone.