BT sputtering at 10 psi

**f15046** · 08-18-2008 08:14 AM

I have a a full gt2871r kit. I have unitronics tune, mafless. The car has been running great, boosting up to 20 psi. Ok now the problem, everytime it hits 10psi the car just stutters and the check engine light flashes, meaning it's misfiring. The only codes it's throwing is " too lean" and "cylinder2 misfire". I have changed the sparkplugs, I have checked almost all hoses and Intercooler piping. So I have no idea what else to look at. If you guys could help me out I would greatly appreciate it.

**AudiRacerS4** · 08-18-2008 08:19 AM

coilpacks

**dwi_gti** · 08-18-2008 08:37 AM

change the coil pack, the offten go

**Don Supreme** · 08-18-2008 08:59 AM

You can also switch that coil pack and see if the misfire moves to the new cylinder for confirmation.

**f15046** · 08-18-2008 07:39 PM

I switched the coilpacks from cylinder #2 to cylinder #3 and I erased the codes, and went for a test drive, and sure enough the misfiring cylinder went to #3 so new coilpacks are on the way. Is it ok that my coilpacks part# is 06B-905-115L and the ones I am ordering are 06B-905-115R?
And why would the misfire only happen when it hits 10psi?

**djwimbo** · 08-18-2008 08:58 PM

Those coil packs are just weird. They decide at random when to misfire.
I had a customer's B6 in the shop that had a misfire. I moved the coilpack from #2 to #4 and somehow the car picked up that #3 and #4 started misfiring after that.

I installed one OEM coil and the car quit misfiring. $27 well spent.

Yes, the part number is fine. A lot of Audi's part numbers get updated over the years.
The first thing they'll change is the letter following the Bosch #.

**Poopie** · 08-18-2008 09:19 PM

you are only boosting 10psi if you are in limp mode and still using the factory n75 valve to control boost.

**f15046** · 08-18-2008 09:36 PM

I'm using a greddy profec b spec II to control boost.

**aaronamerica** · 08-18-2008 09:43 PM

Originally Posted by f15046

I'm using a greddy profec b spec II to control boost.

i would also change your plugs while your at it, what do you have your boost settings at for 20psi

**f15046** · 08-18-2008 10:31 PM

I changed the plugs 800 miles ago. I'm sure it's the coilpacks. And what do you mean, why do I have boost set at 20 psi??

**aaronamerica** · 08-19-2008 05:43 AM

Originally Posted by f15046

I changed the plugs 800 miles ago. I'm sure it's the coilpacks. And what do you mean, why do I have boost set at 20 psi??

no I was saying what do you have your boost settings at to get 20 psi with your greddy boost electronic boost controller, I have the same controller and was trying to compare our settings