Occationally Won't Start

On three occasions since January 2010, the van (4.3 v6, 120xxx miles)won’t start. Turns over great, but no hit. First time after trying all day it finally hit and started, blew black smoke. While starting, smelled like fuel until started. Other 2 times, towed to garage, 1st time started right up 2 days later. 2nd time wouldn’t start, smelled like fuel. Garage took apart upper end check plugs, fuel, and spark, put back together and it started and has run the last 2 weeks. Garage is baffled and has no answers. No start seems to happen after sitting for a couple of days, but is not consistent. Temperatures have varied from freezing to 50 degrees. Need help.

The next time it happens pull the vacuum hose from the fuel pressure regulator (FPR) and look for raw fuel. If you find any replace the FPR. If you don’t find it there suspect a problem with one or more fuel injectors - sending too much fuel.