I have the famous ds header leak between #3 and #5. Also maf pipe has a "few" holes in it. What problems would this cause me? Reason for the ?'s are because my car runs really rich and is missing/stumbling. Thanks
Well, a MAF pipe with holes in it is definitely not good! Not only is the maf sensor unable to accurately read intake air flow, but you have unfiltered air entering your engine! This will cause your stumbling condition. GET THIS FIXED ASAP. You can tempararily fix the maf hose by neatly wrapping it with wide electrical tape.
The header crack can cause slow turbo spool-up and erroneous O2 readings. This will explain your rich condition.
Both need to be repaired but the MAF pipe is the bigger priority.