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Old 01-21-2024, 03:24 PM   #1
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Join Date: May 2023
Location: Oakland, CA
Posts: 144
Diagnostic help needed! Hot film MAF and low oxygen adaptation.

I need some diagnostic help on my 2001 Boxster S. I recently performed some maintenance and a few test drives later got some error codes


- New spark plugs, tubes/o-rings, and coil packs. Test drive was fine no misfires, etc. I burned off some on of the engine cleaner that dripped on the cats, but no issues. (Note: old tubes were leaking, old spark plugs were for a 2.5l not a 3.2l, all old coil packs were fine, but I replaced them anyway).

- Gear oil change - drilled the aluminum pan to access the drain plug. Drained/filled no issue once the plugs finally let loose.

- New fuel filter - replaced the fuel filter with no issue. Started fine after a couple cranks to refill the fuel lines, no leaks, smells, hesitation, etc.

- New engine mount - replaced the worn engine mount with the new 987 style mount. Had a little trouble lowering and raising the engine. I put the jack behind the oil pan toward the transmission near the cable that ties the engine to the chassis. this caused the engine to tilt a little more forward when lowering and made raising it harder. It lowered 3-4 inches and when I raised it back up I squished out some of the fluid in the passenger side transmission mount. I was mad mad mad at myself for not just placing the jack on the oil pan instead. Anyway, car started up fine and ran smoother than ever.


Car was riunning better then every, then on the third or fourth test drive, I was cruising down the highway at about 80-85 mph. I had some right front wheel vibration that I still haven't sorted out yet. Pretty sure the tire is out of balance. Anyway, during that period of vibration, the check engine light beeped and may have flashed. So i pull off the highway and looked over the car. No leaks, smoke, rough idle, noises, etc. So I drove it home slowly hoping it was just a hiccup in the system after all the changes.

The next morning on a cold start the car ran a little rough and made a little rattling on the driver side near the catalytic converter. Sounded like a screw rattling. But it went away after the SAI kicked off (i think). It doesn't rattle everytime, but something is off and its idling just a tad rough.

I got an ODBII code reader and this is what popped up.
P0102 - Hot film MAF Sensor
P1126 - Oxygen sensing adaptation, lower load range, bank 1
P1133 - Oxygen sensing adaptation, lower load range, bank 2


I thought maybe I knocked something loose when I lowered and raised the engine. So I "popped" the hood and started looking around, but nothing seems disconnected on the intake or the SAI. The oil filler tube also seems fine, no big oil leaks or anything. When driving the car in and out of the garage with the engine cover off I can hear a pressure release sound when I give it gas under load. Not sure if that's normal.

I could try a new MAF sensor, but I find it hard to believe the MAF went out right during my test drive window. Is there something obvious I should be checking? I was expecting to find some kind of intake leak or blockage.

Thank you for making through my wall of text!
2001 Boxster S | Triple Black | Stock 17s | Bilstein PSS9s | 9x7 Shift Console

"Sixty percent of the time, it works every time!"
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