kilgore1313
TYF Newbie
- Joined
- Aug 5, 2021
- Posts
- 2
- Reaction score
- 6
This all started a few months ago with the #4 DOD/AFM lifter failing. I didn't have time to do the work myself, so I found a mechanic that was willing to do a DOD delete. We talked and he convinced me that he could unstick the lifter and then turned off the DOD in the software. He also replaced the VLOM with an aftermarket smooth valley plate, did some exhaust work and turned off the E85 tune.
He finished the work and I drove it home. Ran perfectly until I got off the freeway. Then #7 started misfiring badly. I took it back and he said he found #7 had a cracked plug. I paid for plugs and wires and then drove it home.
Ever since then, when the truck is cold and everything is at outside temperature, it will start and drive smoothly for about 1/2 mile. At that point, it warms up enough to start misfiring. It will misfire badly until the engine gets to 210 or so and then it smooths out again. CEL and Traction control lights are flashing. After this I can drive the truck for a whole day with no issues except some minor misfiring at idle. You can feel a little shake at stop lights.
CEL codes are P0300 and P0301
My ODB tool is a little wonky, in that I see current misfire counts on 2 and history on 1, that coupled with the P0301 code makes me think something is going on with 1
I have done the following.
1. Swapped the plug in 1
2. Swapped the wire in 1
3. Swapped the coil for 1
4. Replaced the MAF (Delco)
5. Cleaned the Throttle Body
6. Replaced the MAP (Delphi)
7. Replaced all 4 o2 Sensors (Delco)
8. Replaced fuel injector 1 and all o-rings for the rest (also, 5 and 6. The plastic ring at the top had disintegrated) (Delco)
9. Ran one tank of Lucas Fuel System Cleaner
10. 1/4 of a tank with a bottle of Techron
11. New air filter.
I have tested the compression on cylinder 1 and it comes back at 120, cylinder 3 has 140.
Am I missing anything obvious? I think the next step is for me to start looking for vacuum leaks.
He finished the work and I drove it home. Ran perfectly until I got off the freeway. Then #7 started misfiring badly. I took it back and he said he found #7 had a cracked plug. I paid for plugs and wires and then drove it home.
Ever since then, when the truck is cold and everything is at outside temperature, it will start and drive smoothly for about 1/2 mile. At that point, it warms up enough to start misfiring. It will misfire badly until the engine gets to 210 or so and then it smooths out again. CEL and Traction control lights are flashing. After this I can drive the truck for a whole day with no issues except some minor misfiring at idle. You can feel a little shake at stop lights.
CEL codes are P0300 and P0301
My ODB tool is a little wonky, in that I see current misfire counts on 2 and history on 1, that coupled with the P0301 code makes me think something is going on with 1
I have done the following.
1. Swapped the plug in 1
2. Swapped the wire in 1
3. Swapped the coil for 1
4. Replaced the MAF (Delco)
5. Cleaned the Throttle Body
6. Replaced the MAP (Delphi)
7. Replaced all 4 o2 Sensors (Delco)
8. Replaced fuel injector 1 and all o-rings for the rest (also, 5 and 6. The plastic ring at the top had disintegrated) (Delco)
9. Ran one tank of Lucas Fuel System Cleaner
10. 1/4 of a tank with a bottle of Techron
11. New air filter.
I have tested the compression on cylinder 1 and it comes back at 120, cylinder 3 has 140.
Am I missing anything obvious? I think the next step is for me to start looking for vacuum leaks.
