Go Back   986 Forum - for Porsche Boxster & Cayman Owners > Porsche Boxster & Cayman Forums > Performance and Technical chat

LinkBack Thread Tools Display Modes
Old 05-06-2012, 10:57 AM   #1
Registered User
Join Date: May 2012
Posts: 14
P1126 & P1133. Cutting out/Flat power

Recently purchased a 2002 boxster S and havent yet enjoyed it as the Check engine light came on 100miles after buying it

I have searched the forum to find out the meanings of the codes and problems that surround them.

The problem with the car currently is that it has cut out a few times when pulling up to a stop. It starts back up without trouble but has cut out several times in a row at one point. Also, the power seems very flat and you get what feels like waves of power on full throttle, especially around 5,000rpm. At one point, it felt as though I had taken the engine to the rev limiter as it stopped revings at 4,000rpm. It doesn't feel right driving at a constant speed either, it feels as though its constantly holding back like I am backing off the throttle every second or two.

I scanned the codes and came up with P1126 & P1133

So, I have found out that my engine is running lean on both sides of the engine. I have currently checked for vacuum leaks using the carb cleaner method (being careful around the alternator!). I have checked the oil cap and dipstick tubes which seem ok, can also remove them without a problem with engine running.

What is baffling me is that the symptoms are that of a MAF sensor. But the car went to a Porsche specialist less then 9 months ago for a new MAF sensor and throttle body clean. I have removed the MAF sensor and it is a genuine Bosch sensor and have cleaned it out with electrical cleaner with no effect.

Should I try running the car around with the MAF sensor disconnected?
Has anyone had an issue similar to this?

It has upset me somewhat and would be infinitly grateful of any directions to resolve this problem.


gazrawly is offline   Reply With Quote
Old 05-06-2012, 03:06 PM   #2
Registered User
Join Date: May 2012
Posts: 14
I have just come back from a drive in the car after disconnecting the MAF sensor and it drove perfectly. No flat spots, no partial throttle issues or cutting out troubles. It felt like power had been restored and power delivery was very smooth and progressive. So I would say that given the sensor has been removed from the system and its running perfectly, then the sensor itself would be faulty. Personally I cannot see anything else causing the problems and by disconnecting the MAF it bypass's the other issue.

Any other options, thoughts or past experiences that come to mind are still very much welcomed.

I will order a MAF or try and get this one replaced under warranty if I can within the next week or so and report back to help someone else out in the future who may have this issue also.

gazrawly is offline   Reply With Quote
Old 05-07-2012, 03:22 PM   #3
Registered User
Join Date: May 2012
Posts: 14
Just after some thoughts and feedback on purchasing a new MAF. The current MAF is under warranty as was fitted on 15th august 2011 and has covered just 2,000miles in this time. I am 99% sure it is the MAF that is at fault given research and testing that I have done. I am unsure if a genuine porsche bosch MAF was fitted after reading an article on the Porsche MAF's here...

Porsche Boxster MAF (Mass Air Flow) Sensor

It states the following;
A contact at BOSCH who make the sensors for Porsche admitted to me that there are differences (even though the part numbers are the same!) between the ones sold in the aftermarket in BOSCH boxes and the ones sold to Porsche in Porsche boxes or bags. A genuine sensor from Porsche costs between 300 and 500 depending on the engine model, and the Bosch ones are much cheaper. However, the Bosch items tend not to last as long, are made/calibrated to lower spec's and fail much sooner than the Genuine parts. Its even been said that the ones sold in Bosch boxes are often ones which have failed Porsche quality assurance testing. Also a Genuine item comes with a 2 year garauntee from Porsche, even if installed by an independent specialist.

Does anyone have any thoughts on the above and if I have to shell out on a replacement myself, I presume it is highly advised to seek a replacement from Porsche direct?

gazrawly is offline   Reply With Quote
Old 05-07-2012, 03:25 PM   #4
Registered User
Join Date: May 2012
Posts: 14
Sorry, I have double posted

Last edited by gazrawly; 05-07-2012 at 04:04 PM. Reason: Double post
gazrawly is offline   Reply With Quote
Old 05-07-2012, 06:38 PM   #5
Registered User
DFW02S's Avatar
Join Date: Nov 2010
Location: DFW
Posts: 380
I just replaced 3 O2 sensors that are supposed to be exactly the same as the Porsche parts.
Price diff, $ 80 less per sensor.

I went with the aftermarket product.
DFW02S is offline   Reply With Quote
Old 05-19-2012, 08:38 AM   #6
Registered User
Join Date: May 2012
Posts: 14
Just an update to help anyone else that has this issue in the future...

I had the car plugged into a Bosch diagnostic system and read live data from the Mass air flow sensor on full throttle. The voltage reading was 3volt through the rev range, this should be at least 4volt. I have replaced the MAF sensor and have covered 250miles without fault and it drives very smoothly indeed with plenty of torque throughout the rev range.

Possible cause, faulty MAF sensor fitted 9 months ago OR the new battery that was fitted just before I picked the car up. There is a chance that by jumping the car on a flat battery can blow the MAF so I was told.

Hope this helps anyone with 1126/1133 fault codes.

gazrawly is offline   Reply With Quote
Old 01-28-2015, 01:37 PM   #7
Registered User
Join Date: Mar 2014
Location: Nashville, TN
Posts: 210
my '01 S started throwing a p1126 code about 6 months ago. I cleaned the MAF and reset. it was fine until a few days ago, code came back. about to clean and reset again to see if it works a 2nd time. but it seems that it should not have gotten dirty again so quickly unless there is something else going on.
kiyakubuke is offline   Reply With Quote
Old 01-28-2015, 04:39 PM   #8
Registered User
ELoomis's Avatar
Join Date: Oct 2013
Location: Illinois
Posts: 30
If the MAF is the culprit it would typically show up on both banks. You may have a vacuum leak or an exhaust leak on bank 1.
ELoomis is offline   Reply With Quote
Old 03-18-2020, 04:33 PM   #9
Who's askin'?
maytag's Avatar
Join Date: Mar 2018
Location: Utah
Posts: 2,363
There are a LOT of threads about these two codes..... which I'm sportin' today. So I resurrected just one.


Last year at emissions inspection time, I had already installed the 987 airbox and giant TB. (I think I had the OEM MAF Holder installed though. I can't really remember the order of events there)

This year, I've replaced the engine, transferring all of that over to the new one. I am now running the 987 MAF Holder. I'm ALSO sporting new headers with no cats, mid-pipes with baby-cats, extended-wire o2 sensors, etc.

I'm due for inspection this month, so I went out and did the OBD Readiness Drive-cycle to get it all ready. (I'd reset all codes recently). The first try, I popped a cel right after the 4th/final step; P0420/P0430. These are CAT - related. I rolled my eyes, reset the faults and tried again on my way HOME. This time, different codes: 1126 and 1133. Almost ALL of the reading I'm doing on this forum and elsewhere points to MAF, with the exception of JFP's comments in this thread (LINK): Now frankly, almost anybody else's comments, I'd weigh less heavily against the preponderance of other threads.... but it's JFP, man.

So.... I'd love to hear from others who've swapped to the 987 MAF Holder Tube, and if you;ve had these issues? There's another thread where a user says he put a foam restriction in the 987 maf tube to slow the air, and it passed. ???

C'mon y'alll..... all y'all who've got some experience here, or are knowledgeable about this stuff.... help a brother out?


maytag is offline   Reply With Quote

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -8. The time now is 04:16 PM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.6.0
Copyright 2018 Pelican Parts, LLC - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page