The car is a 2001 S4 6-speed with an older GAIC chip, pigtails, and and APR exhaust.

I've done some searching and most of the P0300 codes listed also have related codes stating which cylanders are missing. Mine only reads as having a P0300 for random misfiring.

The parts have been on the car for a long time, since it was only several thousand miles old. My wife and I have put about 15,000 miles on it. Total miles are just under 100k.

The only thing that it has ever done that seemed out of the ordinary is that it would occasionaly feel like it had a slight stutter to it. It kinda felt like an automatic does when it's shifting into a lower gear.

So, what do you think?

 

id look at the plugs.. with a giac tune rough idle is expected.. your plugs could be getting fouled out.. that code means the ecu notices a slight slow down in crankspeed but its so erratic or intermittent that it cannot distinguish which cylinder it is.. id start with a tune up.. new plugs and a ff...

 

If I were to get some plugs, are there a certain type that is preferred? For example I'm a Subaru guy by nature, I'd usually go with an NGK laser plat that is 1 step colder.

 

yeah, with a tune like that and the higher boost, id go with a colder plug for sure, ive got 1.79 copper autolite plugs in my car, and i just ran a 13.61 at 100mph.. car runs fine, id even gap them a bit smaller, like at .20 or .25

 

Its a common problem on the 2.7T when the 100k mark comes around. The ignition coils are getting weak. I would always get a P0300 after about every 100 miles or so after erasing the codes. It also had a slight shutter when coming to a stop. Change the plugs, if that doesn't fix it, buy ALL 6 coils from www.ecstuning.com, much cheaper to do it that way.

 

Ok, I ordered a new fuel filter & some plugs last night. I ended up going with the plugs that ECS sells. I'm going to give'm a try.

I erased the code too. Is there a certain amount of mileage or time that it normaly takes for the CEL to come back on? Or would it only come back on if it senses the problem again?

 

well, misfires occur under different loads.. it just depends on when the secondary or even primary ignition component fails as to when it will misfire.. on some cars it misfires at idle, others misfire at 25 percent load, others 50, others wide open throttle,... so no telling when or if itll even come back on..

 

Well, I just got done changing out the plugs. The older plugs looked pretty old as I expected. The person who changed them last also neglected to use anti-sieze. They were pretty hard to get out.

The replacement plugs are NGK Laser Platnum PFR6Q. I gapped them to .022" (.559mm). Does that sound right? They came from the factory gapped at about.025" (.635mm).

There is a bit of a rough idle, and the P0300 still seems to be coming back.

 

Is the 6 heat range for a stock engine? I think a 7 heat range
copper spark plug is used in a chipped engine.

 

ECS claims that they should be fine.

I'm looking at their coilpack now, anyone know if the non-OEM are any better or worse than the OEM?