Here's my problem.
This only happens when pulling a load.
Cruising at about 1900rpm, the engine will cut out. It sounds like it miss fires or back firing. Can't tell if it's through the intake or popping through the exhaust. But it's loud and the engine stumbles for about 3 -5 miles..
Now this only happens every now and then. Like yesterday, on an 600 mile trip. I was about 150 miles from home and all of a sudden, the engine started to cough or miss fire or whatever it's doing and it lasted for about 3 miles and then everything was back to normal and it ran fine, just as it was before. I turning the engine brake off or on, has no effect.
This has happened couple of times in the passed few weeks. It's not the fuel. Each time this has happened, the fuel was from a different place.

Any ideas.

 

No lights or codes?

 

Sorry, I should have added that to my post.

Nope, no codes, no lights nothing.
Just driving along and it happens. If this thing had spark plugs and wires, I would've pulled over and check to make sure they were installed in the right firing order. Then tried to figure out which friend switch them on me.

It's really weird. I first thought it was water in the fuel or the filter clogging up. So I replaced the fuel filter, cleaned to air filter. After a week of running around town.(250 miles) I pulled my trailer for 2 day straight and everything was fine( 400 miles). Next day, all warmed up and several miles in to run(150 miles), it happened again.