I just heard from my regular (non-Volvo) mechanic who took a look at the my car (see previous post) and he said that he isolated the missing problem to the #1 cylinder. However, the cylinder IS getting spark, the fuel injector IS working, AND he swapped-out the spark plug --- but to no avail. The cylinder is still dead. He thought that maybe the exaust valve wasn't working properly, but that was just a guess without actually taking anything apart. This engine is an official Volvo-rebuilt one, and has approx. 2,500 miles on it, so I'm finding it hard to believe that anything mechanical is wrong with it. After all, I only replaced an alternator belt on it when it started to run rough. I really, REALLY need some input on this as I don't have a spare car sitting around, and I don't want to possibly ruin my new $3,000 Volvo engine by driving it around with it running on only three cylinders.