1997 F250 HD 5.8 Problem

[swampfox44]

I've got a 1997 F250 HD 4x4 w/5.8. If I leave truck idling for a few minutes after fully warmed up,it surges at idle and shuts off and will not restart for about 10 minutes. It will spin over but acts if it has no fire or either no fuel.
Also,anyone know which mark on timing tab to time engine by? Top flat area or lower indented area? Thanks

[Matts ford]

the coil could be overheating or a distributor issue when you let the truck run. i'd check for spark first, when it shuts down put a tester on it and have someone crank it as you look for spark. if thats not an issue then check for fuel. it has nothing to do with timing or it would not start at all or would run like hell.

[swampfox44]

Yeah,I was thinking possible coil/dist issue as well.Was going to do a spark test.Was wondering if maybe clogged CAT? CAT is smelling really bad,truck only has 150,000 miles. Also,I recently had PCM replaced due to an issue.Was just wondering as far as the timing in general,truck seems to run a bit weaker and sluggish with the new PCM as well as the MPG has dropped drastically. With old PCM,engine had been running in failure management mode and didn't know if previous owner had messed up timing or what.

Thanks

[Matts ford]

well you can try and cut the exhaust right before the cat to see if thats the issue. has the motor been tuned up? you could also change the fuel filter. i'd start off with the cheaper stuff before going crazy on the money.