I have a 1991 F-450 superduty truck we use for a service truck on a Fire Dept. After our truck runs for a while ( when 100 plus outside) it will not start back. The first time it did it it acted like it was in vapor lock. The fuel caps suck in when removed. After it cools down it will start. The front tank is also taking fuel really slow. Out of things to try Help.

I'm having a similar problem with mine. End up squirting WD-40 in the intake all the time to get it restarted. I'm chasing the air leak theory myself. Will let you know if I have any luck.

Thanks for the tip with wd-40. At least it will get us off side of road

Pull the top off of the air cleaner and squirt it directly in. Use plenty for best results. Also, works best if someone is spraying while someone else is cranking. Good luck.