My 1991 Ford F250 feels like it is running out of gas and is not, any hints on what could be wrong

Have you checked fuel pressure with a gauge on both tanks ?

h me perdio el chip de mi llabe como le puedo hacer es mustang

rebuild the tranny, it's about $2500 . make sure they are reputable company.

fuel pressure should be 35 - 45 psi.could have faulty tps sensor.could have intake vacuum leak or ignition timing valve timing off due to worn timing chain.do engine vacuum test replace all vacuum hoses bad leaking egr valve diaphram or gasket will cause engine run poorly.

There may be an internal filter actually inside the tank which may be blocked.

turn the switch on and off about 5 times look on the injector rail there is a valve stem let the air out it has air in the fuel lines

Check on JCWhitney.com they have old trucks parts.

Three possibilities are clogged oil cooler (most likely as you only said while towing) bad fan clutch (easiest to try first) or bad head gaskets.

it may fit but the gearing is gonna be way off, i would not do it

The 7.3 in that year is one of the better ones.
Not much electronics to go wrong.
It is not a Ford engine but a International Truck diesel engine.
It is also used in many larger trucks and racks up high mileage with few problems.
Yours at 200km is almost.......just broken in!

The transmission is the weakest point in the drive line.......run a good BIG trans cooler if you are hauling heavy loads and stay out of overdrive when pulling or hauling anything heavy.