OK. I hate it when I follow a thread all the way to the end and there is no conclusion so here goes. At the beginning of this thread I was fueling up every 150 to 200 miles 22 to 24 gallons. The last tank I went 293 miles on 23.6 gallons, 12.42 miles per gallon. I believe that I can state that this is the first time since I have owned this truck that it went any where close to 300 miles on a tank around town.

The largest change was installing new upstream O2 sensors and a new set of injectors. They went in at the same time so I do not know which of the two made the change or if it was a combination. I also found a tear in the vacuum tube to the fuel pressure regulator which I replaced at the same time. The fuel pressure regulator had no vacuum signal for an unknown period of time and when I put vacuum to it the diaphragm ruptured bleeding a small amount of gas into the plenum. This created a hard hot engine start as it was in effect flooding the engine by filling the plenum with raw gas fumes. The running fuel pressure was low also. It was running at 43 psi and with the vacuum signal disconnected it would jump up to 50. I ordered a new regulator and put it in. I rechecked the fuel pressure and it is now running at 51 psi and with the signal tube disconnected it jumps up to 60 which as near as I can tell is in the range it should be in.

The tank of gas mentioned at the beginning was after installing the O2 sensors and the new injectors but before the new pressure regulator. The pressure regulator went in somewhere in the top half of that tank and for the most part cured the hot start problem. Every change I have made has resulted in the engine running differently until I got enough miles on it for the computer to start re-learning. Right now the truck runs fine but it still occasionally is a little slow starting if I shut it off with the engine hot and leave it sit for about an hour. When it does happen it is the exception not the rule so for the time being I am tired of looking at an open hood and will let it go to see what happens.

I will continue monitoring the in town mileage for a couple of tanks and if it changes after the computer completely re-learns I will update the miles per gallon.

I still haven't ruled out a cam change if I can find someone that will grind what I want.