Been doing some work on my 04 MCS .New 17% Alta pulley ,ATI damper, new tensioner, idler pulley and belt. Has Msd coil, wires and colder range plugs. Have been getting a p0108, asc light on hard accel around 4500-5000 rpm. It has been in the 40 - 50 degree range here. We had a couple of 60 + degree days and I could not get the light on . Added a JCW air box complete with controller, timing chain tensioner and replaced all vacuum lines. Temp has dropped again to 30-40 degrees and now I get the p0108 again and a stutter at 5000 rpm area. It is almost like injector is cutting off and a new problem has occurred, it sounds like it is running on 3 cylinders on start up ,it goes away after a few minutes. Any help would be appreciated. Does anyone know of a good Mini Shop in the north east Maryland area?

 

Sounds like a trip to Helix in Philadelphia is the way to go. You may find someone closer but you won't find a better shop.

///Rich

 

Overboost code, or high circuit voltage in the upstream MAP sensor.

Have you reset the computer adaptions?

It's not too uncommon for some of these cars to see overboost codes in the winter when modified. It has happened to me a couple of times over the past few years.

If it is a constantly recurring issue then you need to do some diagnostic work.

 

Check out this NAM thread here for some very good information. Map sensor here if needed.

 

I am just now getting a chance at an update. Started the diagnostic process, checked all vacuum lines, cleaned both map sensors, cleaned intercooler, checked for exhaust gases in coolant. Everything seemed fine so I decided to check the most obvious , my new cooler heat range ngk plugs. Number 2 plug was firing out the side between the electrodes. Put back in my cheap copper champion plugs and magically no more misfire or stutter at higher rpms. Still can get p0108 in cold weather as it is pushing approx. 18.5 # of boost. So the plan is to wait to see if this a fix or just a bandaid. If it is fixed I have already called Helix to get on the list for a tune. Thanks for the help! I will update again after I drive it a few more miles.