Re: New 350...what kind of problems can leaky exhaust cause?
My FPR (stock diaphragm and spring, new adjustable cap) leaks vacuum slowly when testing it with a vacuum pump. At the upper end (15 to 20 inches) it leaks about an inch of vacuum every 2 seconds, this interval slows down to about 3-4 seconds per inch as the vacuum drops. Is this normal, or are the diaphragms supposed to hold totally steady vacuum? I'm thinking this might be a possible cause of the rich condition. I can smell fuel in the line, but it's nothing like my old set up, where fuel would fly all over the place when you removed the vac line.
Another thought, TunerPro shows no changing value for my MAT sensor. I don't know how much the MAT affects fuel delivery, but it stays at a constant 16 degrees C. I'm thinking this might more of a TunerPro issue (bad .ADS to .ADX conversion or similar) because I'm not getting any DTC's.
Finally, could an overly rich mixture coupled with an exhaust leak cause combustion in the headers that translates to a knock being sensed? Just throwing out ideas.