Had a 2005 truck come in bellowing smoke. It smelled like raw fuel. Codes showed cylinder 3 misfire. Cylinder balance showed cylinders 1, 2, and 3 bad and cylinders 7 and 8 slightly negative -1 to -4. Moved the truck and retested and only cylinder 3 showed bad. Pulled the valve cover and found the injector hold down loose. Pulled the injector and the tip compression washer was half missing and the lower o-ring melted. So compression was blowing up into the fuel rail and caused the unstable readings. Changed the injector and cylinder balance ran perfect. The owner of the truck said that about 2 years ago an injector had come loose while the truck was still under warranty. So, rechecking injector torque when I have valve covers off will be a new item added to the prevention list.

 

Good call, thanks for the helpfull tip, never heard of that happening before but a buddy of mine is having simular problems, might have to check that out

 

I've heard of it a few times, most guys will torque beyond Ford specs now, this is not the first time I've heard of them coming loose. Thanks for the info!