Ok my brother has 87' Jeep comanche with 4.0 liter with 200.000 plus miles on it. In the winter time its starts ok but in the summer it will start when its cold but once it warms up you are stranded it will crank all day but it will not start. I thought fuel injection was supposed to due away with vapor lock so I don't think thats what it is. He says that adding wooden clothes pins on the fuel rail (multi port injection) seem to help the starting problem, but this was near the fall when the weather got cooler. I drove the truck allot this winter and never got stranded. It does seem to crank allot more to start then most fuel injected vehicles then I am use to, I don't know if this will help diagnose the problem.
He bought the truck a year ago in the winter so problem didn't show up till this past summer, and like I said no issues with it this winter.
Thanks in advance for everone's help
Dave