Cylinder contribution imbalance

[hammett88]

When I first start my engine in the mornings I'll get a cylinder contribution imbalance code on number 2 and 8. Also trick runs a little ratty around 1800-2000'ish then smooths out and sounds fine after that. So
Stones truck run smooth and sounds great all together then goes back to running ratty again.. Any clues? Electrical issues maybe?..

[04hdfatboy]

maybe an injector?

[713Diesel]

Some guys have posted some pretty nasty pictures of the inside of the intake manifold caked with a bunch of oil and general gunk. It is possible that his might be so clogged that it is keeping air from getting to a couple of cylinders? This might be magnified if these two cylinders are towards the back of the block. There has been some talk of the back two cylinders not getting enough air due to the design of the intake. Not sure at all on either of these two....... just trying to throw idea's out there.

[hammett88]

Just had the engine rebuilt. Surely they checked for that:/.. Thanks for the help!