I recently did extensive work on my intake system to remedy stalling and general crappy running. One of the very first things I did was to obtain a rebuilt air mass meter from a volvo mechanic friend and install it. After completely dissassembling my intake sytem, repairing an exhaust leak, changing the spark plugs several times, new preheat hose and valve, new idle valve, new coil, new FI tem sensor, rotor, cap, air filters, oil changes to eliminate gas in my oil, I could not remedy a rich running condition that caused my plugs to foul and engine to idle very poorly. It wasn't until I reinstalled my original air mass meter, which apparently was not defective, that my engine was restored to good running condition.

I can only assume that the rebuilt air mass meter I obtained from my buddy to be defective, inspite of his skepticism. Please share experiences with defective rebuilt air mass meters.