Getting misfire codes of 304 and 306. Runs fine in park, clicking in drive. Thoughts?
 

I have a 99 Dodge Ram 5.9 4x4 about 120,000 on the frame and 25,000 on rebuilt engine. Just got check engine light and ran my code reader. I got codes p300, p304, and p306 misfires of course. I looked at plugs and cables and they look fine. Just looking for thoughts on what might be causing the problem(s). Seems odd that they both happened at the same time and that it runs perfectly fine in park. I rev it up and nothing is wrong, run for 15-20 mins no problems. Put it in drive and it sputters and starts making a clicking sound once hitting the gas. I can get up to a decent speed, but hitting the gas makes the click come back.

Check and see if the wires are cross-firing...... Re-route them a bit away from each other.

Wires looked good. I will check again though.

The clicking in drive is suspicious as well....... Can you tell where the noise is coming from? A cracked flexplate would likely play hell with the crank sensor.......

It sounds like it is coming from the right side front of the truck. Hard to tell since it only happens when I'm driving. I will take a look at the crank sensor.

Ok, changed distributor cap, wires, plugs, and rotor. I also put in a fuel cleaning additive and put in high octane on last fill up. I did find my exhaust has a hole in it. Going to fix exhaust and have the catalytic converter looked at just in case there is a clog. Will try to figure out if the clicking is still there after exhaust is fixed. BTW I ran my truck for over 3 hours with no clicking. Though I never put the truck into a gear (drive/reverse). Still scratching my head for a good fix. Codes are now gone, I think changing the items listed above fixed that problem. Now just down to the clicking.