'09 4.8 won't start
The sensors all seem to work. I cleared the light. Also had the battery disconnected for an extended period of time. Tried to run it again. Still runs bad, and after a couple attempts at starting it, the light came back on with a P0106 code.
I have a hypothesis on how my problem came to be. I was able to do spark tests on all of the coils. 2 of them (cylinders 7&8) will light the tester, but the light isn't as strong as the other 6 cylinders. My guess at this point is that the misfire on those 2 cylinders have changed the MAP signal enough for the ECU to decide it isn't happy with the MAP sensor. I may be going out on a limb with this hypothesis, but at least you can see the mental gymnastics I used to arrive at this conclusion. Please feel free to confirm or deny my hunch.
What were the results of the MAP test?
Two weakly firing cylinders shouldn't prevent the engine from starting, but try swapping the plugs/coils around and see if it changes.
Last edited by mountainmanjoe; Feb 11, 2024 at 4:40 PM.
As of yesterday, the engine will start, and high idle. It just runs like garbage. It'll die when it tries to idle down.



