99 F350 7.3 running problems
 

Intermittently it will smoke white run rough loose power...might do it once a week or once a month...drove it 95 mph for 100 miles then it wouldn't run over 75...this is what it does when it decides to act crazy... No engine light only code is a back pressure code that's been in it for 7 years...
Changed
ICP
IPR
LIFT PUMP
AIR FILTER
FUEL FILTER
OIL EVERY 5000 ROTELLA 15-40
CLEANED TANK FILTERS

Could there be a leak of coolant somewhere along the line? Maybe head gaskets?

It's never been low on coolant... It does this on average once a month... Sometimes it's for a few seconds sometimes a few miles then it will run like brand new...

I would get your injectors checked out. Sounds like ones having an issue to me. Maybe I'm wrong but I had a truck that did the same thing but a little more often than yours and when I upgraded injectors the issue went away. :humm:

That's what I was leaning towards but by the time I get it t the shop they can't find a problem grrr