04 6.0l missing

2004 3500 express/savana with 81000 miles

I has a check engine light one. I read the codes and came up with P0300 and P0355.

I replaced the spark plugs, plug wires and coil on #5 and still get the same codes. Any Ideas? Injector, Intake leak? I'm going to check compression and the pins on the coil later, Just looking for some other things to check. Also the Short and Long Term fuel looks a little rich on bank one.

need a little more info.p0355 is a ignition control fault.is the engine missfiring?what are the long and short term fuel trims at.need to know a little more before I can give a good answer.

Yes the motor has a small miss. But only when cold. It will turn on the Check Engine Light when you start it cold. If you let it warm up and clear the codes they don't come back till its cold again. The fuel trim levels are a little different between the 1st and 2nd banks when cold. They don't vary much when warm. What kind of numbers should I be looking at.

as far as fuel trims it should be as close to zero as possible.long and short term fuel trims very.it should be between -10 to +10.but you have a missfire so it will affect fuel trims.I would start by making sure you have spark on the affected cylinder.the pcm controls each ignition control module.seeing as you replaced the coil and plugs and wires the problem lies somewhere else in this system.looking at the diagnostic on the code,it could be a short to ground or pcm problem.not saying this is the wright fix but start here.this type of problem is a little hard to diagnose without seeing the vehicle and how its acting.post back with any other info or results and I can give you more of a better answer.

Can a fuel issue cause a P0355 or is just the coil. What I'm asking is, if I have an injector problem would the P0355 come up, or would that be a different code type.

to answer your question,I would have to say the p0355 code is a ignition control module code,if there is no spark on that cylinder and the injector is still dumping fuel and there is no spark at the spark plug to burn the fuel it would also cause a missfire which would also cause a p0300 (engine missfire)because that cylinder is dead.it would cause that cylinder to flood with gas.you could try switching the spark plug or the ic module with another cylinder and see if it changes to that cylinder.

Update on the missing problem. For everyone with an 04 express and maybe other years, I found that the wiring harness that passes over the left upper a-arm rubbed through the outer casing and into the wires. If your having strange problems look there first. I know this is an old post but I was looking for something else and this one popped up. Hope it helps someone else.