Hoping some expert advice comes my way and helps me get this sorted;
Car - 2013 S4 GIAC Stage 2 + DSG
Gas - 93 oct, never had anything less. Have put in 100 oct in the past to run the race file but not as of recently.
Prior to this episode I have only had 1 misfire and that was in hot weather on the track at around 30k miles. Only had EPC light come on, limp mode. Turned car off and back on and all was well.
Changed all my plugs roughly three months ago to these when I hit 55k miles:
http://www.amazon.com/gp/product/B001B6VUTM?psc=1&redirect=true&ref_=oh_aui_detailpage_o06_s02
Gapped all to .32 (most were right there from the box). Not an OEM direct replacement but was to have been a step up, others have used with out any issue. In addition I am only having issues on cyl 3, I figured if it was a poor plug I would see issues on the other cylinders.
Roughly 30 days later misfire cyl 3 (EPC light and Limp mode) I don’t remember my driving conditions for this one.
Pulled the plugs, checked them and all seemed fine, put them all back in. Two weeks later misfire again on cyl 3, turned car off and back on to clear. Was driving around 2800RPM. A few days later when downshifting at a light (DSG Manual mode) from 3rd to 2nd (peak rpm of around 4200 on the downshift) the EPC light comes back on and limp mode. Turn car off, turn back on and all is well.
Picked up a spare plug, put it in cyl 3 and continued on thinking maybe I had a bad plug. Driving on the highway, S mode 6th gear, 3200rpm…EPC light comes on and limp mode. Turn car off and back on, drive for a few hundred miles and again I go into limp mode but this time throws the engine light on (all other times was just the EPC light).
Turn car off, back on, drive the remaining 500 miles home no issues. Pull the codes, again cyl 3 misfire.
Thinking at this point its the coil pack, I replace it. No issues for a solid month (daily driving, hard driving, etc).
Last week driving around 35mph in D mode and it throws the EPC light and I go into limp mode.
Ive not had any issues on any other cylinders. I have replaced the plug on cyl 3 as well as a new coil pack and swapped coil packs between cyl 3 and 4.
Not sure where to go after all this, only other guess is that its an injector issue. Looked for directions on how to find out if that is the problem (pulling them or logging via Vagcom) and haven’t come up with anything.
Thanks for reading and hope to figure this out.
-AZ