986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - STFT spikes of -98.4% causing P1128/P1130 on 2001 Porsche Boxster. Need Help!

dmboxster · 12-01-2014, 01:52 PM

Thanks for all your replies.

I took it to my local mechanic to have a smoke test done.

Here's what he found:

- I had replaced the Air-Oil Separator myself and it was a PITA. The mechanic said I did a good job getting it all back together but one of the clamps at the bottom was on a little crooked and wasn't sealing properly. So that was causing a small vacuum leak

- There were some leaves that had gotten sucked up into the air box that were preventing some of the air flow to the engine, so he vacuumed that out and got rid of them.

- The throttle body wasn't super clean (no surprise there) so he went ahead and cleaned it all out for me

- The MAF sensor while perfectly clean, did not operate as well as their test MAF in the system. He recommended getting a new MAF and the car should be back to perfect. I'm glad they were able to do the test because a new BOSCH OEM part is $280. I didn't want to spend that unless it was necessary.

Again, I appreciate all your help. Hopefully someone will come on here and it will help them. Without the smoke test, I don't think I would have been able to locate the problem.

12-01-2014, 01:52 PM	#10
dmboxster Registered User Join Date: Nov 2014 Location: California Posts: 17	Thanks for all your replies. I took it to my local mechanic to have a smoke test done. Here's what he found: - I had replaced the Air-Oil Separator myself and it was a PITA. The mechanic said I did a good job getting it all back together but one of the clamps at the bottom was on a little crooked and wasn't sealing properly. So that was causing a small vacuum leak - There were some leaves that had gotten sucked up into the air box that were preventing some of the air flow to the engine, so he vacuumed that out and got rid of them. - The throttle body wasn't super clean (no surprise there) so he went ahead and cleaned it all out for me - The MAF sensor while perfectly clean, did not operate as well as their test MAF in the system. He recommended getting a new MAF and the car should be back to perfect. I'm glad they were able to do the test because a new BOSCH OEM part is $280. I didn't want to spend that unless it was necessary. Again, I appreciate all your help. Hopefully someone will come on here and it will help them. Without the smoke test, I don't think I would have been able to locate the problem.