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[JLR]

I have an '07 Ultra classic cvo that dropped a cylinder while running down the road at approx. 22-2400 rpms. The cylinder is running super rich. I have spark. I checked it with both an inline tester and a tester that jumps a gap. Plugs were new 56 miles before this started. I have changed plugs. Compression is good on both cylinders.

I get codes P0152 and P1356 - Both are for the rear cylinder. Rear cylinder is working, it's the front that is not working. Any clues as to what is going on?

The ultra has been tuned with a TT Master tune. Stock cams and stock pistons. It has a AN air filter and Rinehart true duals and has run this way for many miles.

The codes for the wrong cylinder is confusing.

any ideas??

[TN]

How about spark plug wires, connections too.

WAG 

[OBB]

Switch the plug wires at the coils and see if the trouble moves to the rear cylinder. If so, bad wire/connection. If not, bad coil.

[JLR]

Hey guys,  I'm embarrassed.  The front cylinder had so much soot I assumed it was the cylinder that wasn't firing.  The codes are right,
it is the rear cylinder that is dead.  The rear plug coloring looks good, but? 

Sorry to have led you down the wrong path.

[Ironhorse]

Check the wires under the tank that run to the injectors.  Those are known to become brittle from the heat and crack inside the insulation.

[JLR]

I found the problem.  When I trailered it home the first thing I did was check compression.  Both cylinders were good on my old tester.  After chasing a few different avenues, I thought I best trailer it up to the dealers where they have the equipment to test the fuel pressure and various sensors.  Just for the heck of it I thought I would take another compression test to be able to tell them what I had done and found.  The rear cylinder had no compression.  The lock nut on the intake adjustable push rod had come loose and the push rod was shortening itself.  I was running it a bit on the one cylinder and it finally shortened itself to where the intake valve wasn't opening at all.  I checked the lifter and the cam lobe and all was well.  It runs great again.

[Ironhorse]

The lock nut on the intake adjustable push rod had come loose and the push rod was shortening itself.  I was running it a bit on the one cylinder and it finally shortened itself to where the intake valve wasn't opening at all.

That possibility and the extra weight on the pushrods are the two reasons Jim at Metal Dragon suggested using the OEM stock pushrods when he redid my engine 45k ago. 

Good to hear you got it all worked out.