I'm getting a p0090 code. I've gone through all of the posts here and many others elsewhere over the internet trying to find a solution. This is my first post as I've tried to find others with the same problem and attempt their solutions. I've exhausted that, and at this point I really need some help. I'm fairly handy, though I'm not a mechanic by any means, so if you can provide some detail in your response it would help me a lot. Here's what I've already done. I bought a rebuild kit and replaced all of the seals on the fuel/pump filter assembly. Changed the filter on that twice as well. I changed the fuel pressure regulator and have gone through all of the wiring looking for any damage or wear. The truck currently has 138,xxx miles on it. Injectors were changed by the shop at 126,xxx miles. Basically the truck starts and runs every day for about a week or so, then it may not start for a few days or longer. I haven't noticed any link between the time of day or temperature and the no starts. I've even encountered a no start after driving the truck, going into a store for a short time then attempting to start the truck that was running 20 minutes prior. When it doesn't start I have pumped and primed the fuel filter assembly repeatedly in between starts (loosen screw, pump it up tighten screw and pump it a couple more times). I've even followed the procedure for primng the system like you would after an injector change. I would truly appreciate any advice as to what should be checked and in what order. Thank you - David

 

Getting P0540 as well. Changed Air Intake Heater Relay but still getting the code. I don't know how to test the relay I replaced to be sure that it is bad. I'm in Arizona so I don't believe I even need this to start the truck but it could be related to a bad ECM from what I've read. Any advice is appreciated. Thank you - David