All of those situations would have been at low/closed throttle. If the engine was getting too much fuel for the amount of air it was taking it that would cause a backfire/afterfire as the unburnt fuel ignited in the exhaust.

I'm going to go with bad TPS, MAP, or something else that would make you get too much fuel when the throttle body snaps closed. maybe a hanging injector?

 

I changed the TPS a few months age, Maybe I will change the fuel filter and run a can of seafoam through it. Another Weird (but good thing) is I only got 8 mpg pulling my trailer (acceptable) but this last week I have ran to work and back and got 12 mpg. (usually 11.)

 

Sorry to revive a year old thread but after pulling the same trailer up the same roads as last year it is still acting up.
Truck pulls great for 110 miles, when I exit the freeway and head down the last 30 mile stretch the truck bogs like crazy. 55 mph max. if I push in the clutch and rev it to 3800 it will backfire when I let off, after doing this a couple of times it clears up and runs fine. TPS, MAP, EGR position sensor, fuel filter, are all new (within the last year) No codes, just 11/11 all good.
Any ideas?? I am stumped, This is my daily driver and I never have any problems unless I work it hard.

 

Check for fuel leaking thru the regulator into the vacuum hose. Then check fuel pressure. You may have to rig up a gauge sticking out of the hood and drive it a while.

 

Don't go up that hill anymore. Problem solved

 

Thanks, I will check the Regulator, and pressure,
And my wife also told me to quit driving up the canyons, but that would mean not enjoying our mountain property. LOL

 

New to the site, and I see that this is a very old post.... My question is, there are references to "CHECK THE CODES", I have a 1988 F 250 FI 460 (7.5 liter) that doesnt have a OBD II port of any kind, how would I read any codes?

 

Read this link:
Fuel Injection Technical Library » How To Run a Self-Test

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