Dark_horse

Background: 991.2 with m660 Tial turbos, headers, sport cats, tuned by M Engineering on E40 on Cobb. 40k miles on car now.

I’ve been noticing more and more that my car will randomly sputter under moderate to hard acceleration when in gears 3,4,5. No other issues that I’ve noticed. This sounds and feels like spark blowout or coils. This was the same symptom I had with my previous turbocharged Mr2 and after changing the spark plug wires the sputtering went away.

I searched and couldn’t find much regarding high powered 991.2 and spark plugs. Like for instance running cooler plugs or changing the gap. Also when should the coils be changed out. I’m thinking it’s an ignition problem based on my previous experience. Spark plugs were changed at 30k miles.

Foosh

Sounds like coils/spark plugs to me too. If they've not been changed in 40K miles, that's the first thing I'd try.

Kitc2246

Pull codes first. Could be bad gas, gas filter, etc. Turbos are hard on plugs. With a tune even more so. If you change the plugs doing the coil packs is common since it is no more labor.

B Russ

If you data log with your cobb and send the file to M guys, I bet they will tell you

Dark_horse

Only spark plugs were changed not the coil packs. Also there are no codes that come up. Data logging and sending it to M Engineering is a good idea and something that I’ll do first.

doctj

Had/have same issue in higher gears and lower RPMs (same mods as you) . M engineering as well. . Was a misfire , and was not in all rpms or gears so likelihood of coils/plugs is low and might be a tuning issue. (Plugs new , 11k miles total on car)

my issue isn’t resolved.

let me know what you get on your end

Dark_horse

did your issue happen right after the tune because mine had been fine for a while but just recently started experiencing this.

Will keep you posted. I’ll try out a few things.

Sulzy

did you work it out? I have seen similar sputtering that corelates with the IAT reporting above 66°C. My conclusion was heat soak of the ICs.

Dark_horse

I never looked into it afterwards. It actually hasn’t happened since I posted. I’ve driven it pretty hard.

The times it did happen was when it was cold out so maybe that has something to do with it.

4 Point 0

I always gap my plugs down to 0.020

There weren’t any colder plugs available last change so i’ve always run OEM gapped down.

Dark_horse

I had an Indy shop replace mine at 30k miles. I’m sure they used stock plugs and gap. Car was stock at the time so it was all good, however the car is now highly modified and perhaps it’s time for some new plugs and a smaller gap.

Any colder plugs available now?

Viper1000

Wouldn't it be showing a code if it's missing. I would see if anyone local has a OBD reader or even your local Autozone should be able to read it.....

Dark_horse

No cel ever pops up. Plus I have a OBD reader and no codes.

Viper1000

Interesting now that we know it's not "having issues" at least that the ECU is identifying. I wonder if it's bad gas then or even gas with a lot of condensation in it? Interesting!!!!

4 Point 0

None that I have heard of. If you find one, be sure and report back.

I’m on TiAL M800’s with E40 tune and still no issues with just fresh OEM gapped down.

I over service my car due to tracking. So this is my third set of plugs in 37,000 km’s. (Never had to, just more of a whilst we are in there deal.)