HELP! Threw a code P1128 have ODB info

My car has thrown this code a few times and I have cleared it. Finally I am gathering the diagnostic info and its in this message, can someone tell me how to fix? CODE P1128 Calc Load 4.7 Coolant Temp 201 Short term fuel trim, B1 -2.65% Long term fuel trim B1 0.655% Short term B2 -3.65 Long term B2 0.655% RPM 819 Ignition Advance 7 degrees Intake Air temp 153 deg F Air Flow 0.91b/m Throttle 3.1% Oxy B1, S1 845mv Oxy B1, S1 (Fuel trim) -5.65% Oxy B1, S2 820mv Oxy B1, S2 (Fuel Trim) 99.2% Oxy B2, S1 825mv Oxy B2, S1 (Fuel trim) -6.65% Oxy B2, S2 815mv Oxy B2, S2 (Fuel trim) 99.2% Does anyone know based on the above what I should do?

Bump. Does anyone have an answer on this? I included all the oxygen fuel trim info etc, which is what most people dont have when they post these codes. Just trying to figure out a game plan to fix this. I hear alot say spray electronics cleaner on the maf and then spray carb cleaner into the throttle body.........i could try that, just need to buy the special torx wrenches for the maf.

Well, you idle MAF reading is fine, maybe slightly high. Intake temp is very high leading me to believe that the MAF is the culprit. Calculated load is very high also. Do you have the stock air filter setup? Have you sprayed the MAF with electronic's cleaner to remove residue? Has there been an increase in your oil usage? The P1128 is reporting that bank 1 is running lean, either because of to much air or too little fuel. The amount of fuel is partially determined by a calculation of intake air temp, load and volume of air. I would suggest first cleaning MAF and test again before moving to more difficult diagnosis.

Car was idle when I took those mesurements. I have the stock air box and stock porsche brand air filter changed maybe 2 months ago. I have never sprayed the MAF/cleaned it. I have owned the car for about 20k miles, car has 50k on it. No increase in oil usage, I really never add oil. I changed the oil maybe 2 months ago (every 15k miles) with mobile 1 ow40, factory filter, etc. My car does not leak a drop. I bought the security torx tonight, and was going to pull the MAF and spray it and let it dry, then reinstall to see if that helps. I have been throwing this code every 5k miles or so. The last time it happened, I shot a bottle of Techron into the tank to help clean any injectors, but that doesn't seem to have fixed anything. I will clean the MAF, reset the computer (disconnect battery for a few minutes) and then take new ODBII readings......thanks, appreciate the help. Brian

Dude, just put a new Air Mass Meter in it and be done with it, don't try to clean it. Your RKAT's and FRA's are a typical Air Mass Meter.

They aren't exactly cheap.....$300 or so for a MAF, and it could be something else right? like an injector or an O2 sensor? I think cleaning the MAF is simple enough to "try" it.

02 sensor faults would throw 02 sensor faults, injector = misfire faults (have yet to see a problem with an injector FYI), put an air mass meter in it, clear the fault, and enjoy your car for another 50,000 miles until you need another one, lol. Or you can check for a vacuum leak if you must. Doubtful you will find anything, but if you must. No vacuum leaks, put an Air Mass Meter in.

Whoops, my bad, I have food on the mind, making dinner, lol. Don't check for a vacuum leak because you don't have one, your RKAT's and FRA's would both be positive. Air Mass Meter

Working through a MAF issue myself right now. So Adaption, range 2 (FRA), bank 1: 1.29% Adaption, range 2 (FRA), bank 2: 1.30% Adaption, range 1(RKAT), bank 1: -1.78 Adaption, range 1(RKAT), bank 2: -1.64 rules out a vacuum leak?

No, it does not rule out vacuum leak. A vacuum leak would cause O2 sensors to add more fuel which would increase your FRA. But, so would dirty injectors, dirty or bad MAF and several other things.

Yes is does rule out a vacuum leak!!! Both RKAT's and FRA's would be positive RKAT's in your little quote are negative, therefore taking away fuel, running rich, lack of air for the amount of fuel injected. Adaption range 1 is not positive therefore there is no vacuum leak. AIR MASS METER. FYI, your FRA's are higher load range, higher rpm, where vacuum is really non-existant

Yes is does rule out a vacuum leak!!! Both RKAT's and FRA's would be positive RKAT's in your little quote are negative, therefore taking away fuel, running rich, lack of air for the amount of fuel injected. Adaption range 1 is not positive therefore there is no vacuum leak. AIR MASS METER. FYI, your FRA's are higher load range, higher rpm, where vacuum is really non-existant

sorry about the double post, thought i lost my internet connection for a moment there, i wish i had a Mac, lol

Long term fuel trim takes up the correction factor of the short term fuel trim, and therefore the STFT will not necessarily ( and most often will not) show adding fuel when there is a vacuum leak. The LTFT will show the added fuel. Therefore, you cannot rule out a vaccum leak just because STFT is negative. Your statement of "FYI, your FRA's are higher load range, higher rpm, where vacuum is really non-existant" is not correct, and I have no idea what hat you pulled that out of.

Short term fuel trim will always show a vacuum leak first, Long term fuel trim will follow accordingly the longer the engine is driven with the vacuum leak, hence why they call it SHORT TERM and LONG TERM

If you have a constant vacuum leak for more than a single drive around town, your LTFT will take up the slack and your STFT will look normal. The STFT will always try to find neutral and reflects immediate need for more or less fuel. So, unless you have an ever changing vacuum leak, LTFT will adjust up to it's maximum. A little reading on the subject would help you understand the relationship.

All of your statement is true, if the engine had a vacuum leak that the DME can compensate for, aka, adjusting the fuel trim, if the DME were able to compensate for it yes, you FRA's (LTFT) would go positive and eventually your RKAT's (STFT) would steady around 0, but there would be no fault codes thrown, therefore would never see a problem or notice one because the dme would compensate for it, however, we are talking about P1128 <-- a fault code that the DME put out, idle range adaption fault code, bank 1 i think, his numbers were NEGATIVE on both banks, therefore no vacuum leak, AIR MASS METER at fault

Well, then you agree with me when I suspect the MAF as I indicated long ago in this thread. However, the question was posed whether the fuel trim readings provided ruled out a vacuum leak....which I explained why....it does not. Again, his negative STFT readings can not be used to determine whether there is a vacuum leak or not nor do they give any indication of what the overall fuel adjustment is. It is his LTFT that tells you fuel is being added to a greater degree than normal.

So where is a good post or website that explains basic ODBII MAF/oxygen/fuel trim info and how to read it? This is good stuff..........

http://www.ross-tech.com/vag-com/cars/fuel-trim.html http://www.stealth316.com/misc/wells...el%20trims.pdf

"Again, his negative STFT readings can not be used to determine whether there is a vacuum leak or not nor do they give any indication of what the overall fuel adjustment is." <----- THEN WHY ARE THEY THERE, just for good looks. Let's start with what is happening in the engine right now, Oxygen sensing values, instant <--- (I don't know if you can read those with code readers, I doubt it,) those will adapt the RKAT's (STFT), then those will adapt your FRA's (LTFT), or with the new car's (9X7) Oxygen sensing values adapt your RKAT's, RKAT's will adapt your FRAU's, FRAU's will adapt your FRAO's, you have your LTFT and STFT backwards, any questions???

If you have a vacuum leak, the DME will see the oxygen sensing number start to climb (adding fuel), which will push up your RKAT's, which will drive up your FRA's eventually, but wait, the RKAT's were not positive they were negetive, taking away fuel, oh no, NO VACUUM LEAK !!! Good night

Ahh, a sure sign of a lost arguement....slowly changing the topic to fit more with your side of the debate. We are talking about a constant vacuum leak here and nothing else. Obviously the STFT will change and it changes constantly and continuously whenever the engine is running. A 3% change in STFT one way or the other is an indication of nothing except that the system is working properly. If all of a sudden you popped a vacuum leak, then the STFT WOULD turn positive, but only for a short while until the LTFT took up the slack, then the STFT would return to normal. The same result would occur with a bad MAF. If the MAF is indicating less air than is actually getting to the engine, then the STFT would temporarily add fuel until the LTFT adjusted for the increase. You have made no mention of the tremendous increase in the LTFT indicated. I guess you think this is because the is too MUCH fuel? If you understood the system, you would easily see the failure in your arguement.

A constant vacuum leak, small enough for the DME to compensate for, oxygen sensing will eventually steady out around 1.00, RKAT will be slightly positive, FRA's probably will not change anymore positive than the RKAT's <----------RKAT's will never zero out, will always be positive, why, because there will always be a vacuum leak, small or not, it will always have to compensate for a vacuum leak by adding fuel, ONCE AGAIN LIKE I SAID BEFORE RKAT's are idle range, FRA's are UPPER rpm and HIGHER LOAD range, IF YOU knew the PORSCHE system and not a Ford or Chevy system with old STFT and LTFT, you might understand the real meaning of RKAT's and FRA's, and new car's RKAT, FRAU, and FRAO, there is a difference A constant vacuum leak, large enough that the DME cannot compensate for, oxygen sensing numbers, 1.25, RKAT full positive, FRA, full positive, check engine light on, <---- this right hear, RKAT will never zero out in this situation, always will stay full positive, the DME cannot add anymore fuel to compensate for the enormous vacuum leak

FWIW, and not to get into an obviously heated debate, I had a similar problem with my 99 C2. I finally changed the oil/air separator bellows. No more CEL. The bellows was a mess, totally falling apart. And the CEL's got progressively more frequent. Noticed it most at idle or very very low load. It is an easy DIY and the part is cheap. I'd highly recommend examining it and replacing it. The bellows is rubber and is apparently notorious for cracking and creating vacuum leaks. Again, I'm just speaking from personal experience with my car and similar codes.