Wired things happen from time to time, and they can eat your lunch, when your trying to figure things out. I have a friend that was having a similar issue, with his truck. Not to say that this is your issue, but, after tring a bunch of other things, he finally decides to replace his fuel filter. After that, the truck was fixed, so, he cuts the old filter open. He finds a dead bee, inside. The bee, would get sucked up into the output hole, blocking off the flow of gas. Point is, sometimes its not the obvious. Simply, your truck is starving for fuel, from what I have read. I am not there to run test myself, so all I can do is say this. Do your research into what all controls your fuel delivery. IMO, that's where your issue is. I haven't had an OBD1 vehicle in well over 10 years, so I don't remember all of the little in's and outs, but I do know this. Not every sensor controls fuel delivery.