Need 2nd opinion on P1128 mass air flow sensor diagnosis
 

Hey everybody, my girlfriend is selling her 2000 986 S and it is throwing a CEL It is a P1128. I can defeat it with an OBDII but it comes back after a few drive cycles and has a very noticeable flat spot around 4500-5000 R's with 50% throttle and above. Additionally the idle sporadically revs +3-400 r's when stopped. Car runs and drives very well in lower R's and you wouldn't even know it had an issue. I opened it up and hosed down the MAS with MAS cleaner and it did not cure it but the air filter was pretty dirty and she couldn't remember last time it had been replaced. The car has 56000 miles on the clock.

Thanks for any help

Doug

Search this forum for "P1128"...

and read this:

http://sites.google.com/site/mikefocke2/checkenginelightcausedbymassairflowsensor

My 99 was putting out a 1128 and a 1130. I had the same miss at 5K. I changed the MAF and it cured the problem. My car has not run better sice I bought it. 82,500 miles. Good luck, Bill

Cleaning the maf prob won't work. The maf is a wear part, it evrntualy needs to be replaced, so I would change it .

If u r trading the car on save your money, they will jack you on the trade price and don't care much about that stiff. If u r prov party selling I'd fox it. Cheap to eplace and if the car sputters on a test drive no one but a fol will buy it

So I opened it again today and put a new air filter in and I actually pulled the MAF out of the intake and cleaned it again, no change but wanted to comment that the MAF looked very clean, neither the enclosed wire or the one on the side had a spec of dirt on it, albeit I hosed it down a few days ago. I guess I am expecting some obvious sign that it has failed. I can't order the part until tomorrow so still fiddling with it. Should I unplug it and drive it around the block? Also, it is throwing a P1133 now instead of the P1128 the first two times I scanned it. The car still runs pretty well minus the flat spot and occasional surging idle.

I had the same codes and went through several cycles of cleaning, same as with you it looked good
Well, after I finally replaced it the codes went away and never came back ...

Hi i had the same problem and i cleaned the throttle actuator and that took care of the problem. hope this helps i also replaced my air flow meter and that didnt make any inprovement. pedros garage has instructions if you need them.