Ford 25= Deisel missing at 65mph

[Montana_2008]

I have a Ford 250 6.o and I am getting a miss and backfire at 65 miles an hour. I pull a Mont. 3400 with no problem. I can drop down to 60 and it stops or I can speed up to 70 and it stops. I added a 4 inch exhaust and an airaid to the truck, get 12 miles to a gallon with monty anyone else having this problem is so please e mail me MtMan1313@aol.com Thanks

[lightningjack11]

I have heard the 6L's have been having headgasket problems. It sounds like it may be crossfiring between cylinders when your compression exceeds a threshold. Unfortunately if this is the case it will get worse. Suggest you go the www.thedieselstop.com and check with the forum members in the 6.0L section. My best guess

[Sweetfire]

What year Ford? When you put the 4 inch exhaust on did you remove the catalytic converter? Did the backfiring start after one of the mods?

[trukdoc]

I have an 05 6.0 L and have had absolutely no problems towing...knock on wood. And of the other 6.0L I know of I have not heard of the problem. the 03's are the only ones I have heard having injector problems.

[drhowell]

My 04 has 25,000 miles and no problems. Not sure about Lightning Jack's suggestion about head gasket leak and cross firing at certain speeds. Usually head gaskets show at all speeds and normally accompanied with a water leak. Interesting that under load (speeding up to 70) it doesn't miss. I would think it has to do with the mods and some kind of air leak.

[Montana_5008]

Mtmn 1313, I have a "99" 7.3 and I developed a miss at certain speeds and then it got worse.We put the meter on the truck computer and it told us it was valve cover gaskets?? The injectors are inside the valve covers along w/ the glow plugs.So guess where they put the wiring harness,in the valve cover gaskets. I had a wire that was burned to another wire on the right bank. I suggest to put a meter on the computer and it most likely will tell you what the problem is with that 6.0. Rascal

[wa4bmg]

We have a 6.0 2003 late build date with 65,000 miles and no problems with injectors or gaskets. In 2003 the early models did experience injecter problems with the 6.0 but the anything built after May 03 was to have the new injectors. Ours was built in Aug. Just some thoughts

wa4bmg

[lightningjack11]

Farmer Don,

It was only a guess. On gassers sometimes crossfiring will not leak water and missing will occur at different speeds if head leakage is a small amount. But by all means coolant in the oil should be checked along with reservoir coolant levels.

Also before major maintenance the computer codes should be read out. My reader on my old 97 will read out about 256 codes that could give a clue of the problem. Reading the codes would be the first thing to do for troubleshooting after coolant checks.