Hey guys. 03 996 Turbo with EPL tune. I have been messing with my other cars a lot lately and probably haven't driven my 996 in about 12 months or so. She started up great and idled really smoothly, but just cut out/sputtered bad with load in any gear when I took her out today. Not much load and feels like the timing is pulling back ( A problem I fixed with higher octane fuel in the hot desert in the past ). Cool out today. I haven't felt her sputter like this though. Not much load. I have read a lot about MAF or boost leak, but I think that would not happen just sitting in the garage. My guess is 1/2 tank of gas is getting bad. My plugs must have less than 8K on them, but I did use the thick copper plugs many of you guys recommended back when I replaced those, so doubt it is that. I did red line her once the last time I drove her because I missed a shift pretty badly from 1st to second. opps....I have a Durametric cable, so what would you guys suggest I look at first? I'm gonna putt around the area tomorrow and run the old gas out without loading her at all. I'll then run a gas/Toluene mix a Porsche racer taught me about around 15 years ago. I have been running this mixture in my 300ZX Twin Turbo and boosting to 23PSI on a regular bases. I never had a sputter using this mix ever in the past. I get them to 95 octane on ea. car and it really helps when it's hot in the desert...over 110 degrees and still no knock. Anyway, any other thoughts or suggestions would be appreciated. I did find a chewed wire from a dang mouse, but fixed that...Engine lid wire was chewed right by the switch next to the driver's seat. I have traps everywhere in my garage now. So look at MAF and coils first? Or run the gas out and see if that helps? It's been a really long time since I worked on my Porsche, so what are the normal readings again on the MAF? I have no lights popping up. Any suggestions would be appreciated. Thx.

Has anyone had luck with these?

https://www.ecstuning.com/b-assemble...760210700ikt2/

Thx

Beru coils and whatever plugs your tuner says.
I use fr6ldc.

I was gonna add those look like the old style bolts the internal torx. IIRC the new style bolts are external torx. I'd call them to confirm.

You want the 997 p/n coil packs, the plugs mentioned above and the updated bolts. Should be good to go if it has all those.

Update: It's not boosting over 0.4 or at the very most 0.5 Bar. My tune boosts it to 1.3 bar. It does not sputter until it starts building boost pressure. The new gas helped it run great until I started to boost, then jerk and sputter again. It also just threw a code, but my laptop is dead, so waiting to charge and read what code. I'm thinking boost leak now, but I'll see what code shows up in an hour or so. I also have a new exhaust with only 200 cell cats. Wondering If that has anything to do with it....Ox sensors? Thanks for the comments. Can anyone put up a link to the 997 type coils just in case I go on and replace those anyway? Appreciate it guys. Thx

Update: Hesitant acceleration noted, but throttle body values look fine. MAF reading is 19 kg/h at idle. (My guess is MAF) I had 2 codes: P1133 and P1126. (Both banks oxygen sensing adaptation in lower load range) Leakage volumetric flow is zero.
So...Think it may be the MAF? I did see a quick cylinder 6 misfire pop up, but then did not come back again when I was testing each cylinder. Hummm?

Any input from all you super Porsche mechanic dudes or babes? I could sure use some advice B4 just buying new O2 sensors or MAF. Possibly off from my new exhaust? I'll wait for some replies B4 I try and clean the MAF first. I NEVER used oiled air filters BTW. Thx for any help...

Unplug the MAF, and test.

I dont think its bc your exhaust. I put mine on and had no problems for a couple years before I ever got a tune. Its likely your MAF.

My opinion is that o2 sensors are wear items. Just the smart ones, the upstream ones. If your MAF is bad just get the 2 new o2 sensors to go with it... that's my style anyway. Especially if they're original. Its 2020 your car is at least 15yrs old.

I did my new upstream o2 sensors right before I got my tune about a year ago

OK...MAF voltage is 1.34 warm. That is within the normal range right? It was 1.04 not running, which I believe is also normal. Plz help. Are those value correct? where do I go from here?
The strange thing is that unplugging the MAF seems to make no change at all, which makes me think it's still the MAF. I'm not sure where to go from here.
Hot film MAF= 1.30V
Cam position 1 deviation= -2.59
Cam position 2 deviation= -5.28
Loss adaptation idle= -1.69

Money is definitely a limiting factor as I now have PTSD and have not been able to work for over 2 years. I'm in a bind. I think I'll try cleaning it first and see, but not sure what after that.
Thanks guys.

given you mentioned redlining the car briefly and that you have ( presumably ) a "1.2" tune, it's entirely possible that pegging the limiter, fried the maf. common on tuned cars as the maf circuits "understandably" prefer a "stock" car/ecu.

as others have suggested, unplug the maf and run the car for a bit, and see if the sputtering stops. the car won't run "as it should", but it will help you to determine if the bosch 124.00 is toast.

other than that? plugs and coils are the traditional first things to eliminate when chasing problems, such as you're having. GL w it.

Cleaned the MAF and still sputtering, but did get her to boost to 0.9 Bar. Was only getting 0.5 max b4. I did not unplug the battery because I have close to 50 electronic settings on my stereo system I don't want to deal with right now.
I did notice the MAF was not tightened down very well. Cleaned several other sensors and all the wires and plugs on top look great. No ideas? I wish I had a lift...Can anyone tell me what I should be looking for on the Durametric readings for my upstream O2 sensors? Probably look there next. I'll drive her when I can get some time and see if anything adjusts on it's own. Revs at idle have improved a lot!

Yep. I have read about redlining a tuned, or much higher HP than stock, car can indeed fry the MAF, but again the readings do not appear to be off. Do they? Funny my 300ZX TT has just about double the factory HP and I run 2 MAFs now with a Selin translator and all that costs less than one "Porsche" MAF. haha. I'm really starting to think I just let her sit for too long and my gas is bad. It is slowly improving some just about every time I do something and drive more. I hope this gets figured out soon. I'm kinda obsessing about it. I really appreciate the input guys. Thanks.

I wish I could tell you what the MAF values are supposed to be. I dont know, hopefully someone else does.

I do want to add that last month I accidentally started my car with the MAF unplugged and it went haywire!! Gave me all kinds of dash lights and ABS warnings, I can't remeber all the details but it was scary, I thought I messed up big time. Plugged it back in and and did the old battery reset (left the negative off for 15 mins or whatever) and she went right back to normal.

At this point you need to step back and evaluate the situation and proceed with the simple things.
First off, get rid of the suspected BAD Gas. Simple to do. We have all been there with the bad gas thing. It's not good.
Unfortunately as you move forward with the process of elimination with clues others have given it can become costly. Plugs and coils can still be suspect even though you may have changed them recently. O2 sensors are also suspect if never changed. As well as your MAF.
I can tell you this from experience, when all is said and done and you get the car running normal again, DO A BOOST LEAK TEST. It is very simple and you would be surprised at what you might find. Most are. I know I was.
On another note, if it helps I have a tuned car that I went MAFless. I do have a good MAF sensor and some good O2 sensors I can lend you for testing.
I can send them to you with the promise that they will be returned.
Just a friendly offer !

"cleaning" the maf ( always a dubious proposition anyway ) will not correct a "fried" maf. also, the way the maf sits in the receptacle it's either "in" or not as there is the pressure required to "click" it into place. the 2 t20 screws don't do much either other than keep it snug when tamped down.

this reads more and more like bad fuel as you indicated when you added fresh fuel it ran "better". i would run out ALL the old fuel and begin anew.

it all reminds me of the one time i mistakenly put 89 octane into my old triumph bonneville and it only seemed to run on one of its two cylinders! a trip to the auto parts store and bit of octane booster and fresh 91 cured the issue. but until i did that? it barely ran at all! again GL.