My '05 F250 has been down for a week now. It started with the truck running horribly and stalling. I could restart it after a number of attempts, but it wouldn't go much over 20 MPH and missing terribly and stalling after about a 1/4 mile. It was throwing a PO263 code , #1 injector contribution. I took it to my mechanic. Buzz test kept throwing random injectors, so they replaced crank sensor. It then only showed #1 injector, so they replaced it. No change. He tells me a little while ago they ran more diagnostics and shut off the passenger side bank it was OK, shut off driver side it showed entire passenger bank not working, then an exhaust restriction problem. They removed catalytic converter no help.He is scratching his head and I'm getting pissed. Any ideas what he should be looking for?