TT Surgeon

Annoying issue.
At full boost 1.2bar at wot car cuts out/stumbles badly at 5500-6000rpm, otherwise runs good. Doesn't really happen in non sport mode. Reminds me of my 930 when the boost hose was leaking at the ic. Had a cel a few weeks ago, probable maf, cleaned the sensors and cleared code, never came back, but still cuts out. I did find the maf housing ribbed hose very loose/off at the time. Tightened up, still cuts out. Maybe maf is shot?
I'm thinking plugs n coils, have them just haven't had time to install.
Thoughts?
C

A418t81

Given previous MAF codes, I'm inclined to lean in that direction. Plugs/coils typically begin to manifest their issues at peak torque, where cylinder pressure and resistance across the electrode is at maximum. Bosch MAFs typically don't tolerate cleaning very well, despite the status quo on the forums. I worked for APR when I was in college, and back then any type of MAF code from a Bosch maf = replace. The maf is less expensive and easier to replace than the plugs/coils. I would probably start there. Factory air filter or BMC?

It most likely doesn't do it in non-sport mode because the overboost function isn't enabled then, so 2-3 psi less boost.

TT Surgeon

Good point, stock filter.

Kevin

Do you remember the tripped code? Post it..

I'd also check your plenum and FPR control line connections.

therock88

I am thinking plugs too. At wot in Sport mode at that rpm....plugs can definitely do it. I have had a similar issue in past and plugs cured it. I think it was misfiring.....I called it "sputtering".

Good luck.
DC

A418t81

I had issues with misfiring when I first was getting my car up and running and it was clearly the plugs. The car had 38k on the ODO and I figured they were the original ones. Like I said above though, it started misfiring at peak torque. It's kind of weird that it misfires at 5500-6k and is clean on either side of that range.

How old are the coils and plugs? If you think they may be original that's likely the culprit. Thinking about it more, if the turbo inlet pipe was basically falling off the maf that could definitely throw some plausibility codes as the majority of the air being pulled in would be unmetered.

TT Surgeon

Plugs n coils likely original, when I did the coolant lines the tech 'forgot' to do the plugs as I asked. I think the code was p2097, rich bank1 usually maf. All other lines looked good. Wouldn't that turbo inlet tube cause a boost leak?
It's definitely "sputtering" is what it's doing, once it starts I back off so it probably does continue above 6k.

A418t81

The accordion pipe attaches to the back of the maf so the turbo is drawing air through the maf sensor where the air mass can be metered. That wouldn't cause a boost leak because the turbo inlet pipe and maf sit ahead of the turbo, pressurized charge air is after the turbo. It does pose an issue with correct measurement of the air mass obviously. The ECU is looking at fueling the whole time though and will correct fueling to some degree, but will notice that the maf isn't symmetric with the other side and that fueling is requiring large amounts of trimming to bring into commanded spec, hence the code(s).

TT Surgeon

Gotcha

CincyScott

Methinks it's time for a tune up, Mr. Surgeon

CT944

Is clutch slippage at that power level a possibility?

TT Surgeon

Yep, my knuckles are dreading the plugs..........
Clutch is a gt2 unit, new no issues, def not slipping.

atcbi5

I would do coils and plugs.

therock88

Use my DIY guide. Not that bad, and your knuckles will be fine! Just take your time....

Good luck,
DC