My 2002 Dodge Ram has a persistent miss. It has the 4.7 4x4. Over the last few years I have constantly been fighting it. About 1 1/2 years ago I put in all new plugs and coil packs. I have since replace 3 of the coil packs.

Whenever I replace something the truck runs good for a while and then the miss comes back. The codes will say something like Miss Cyl 8 and Intermittent miss Cyl 4. Now the engine has started idling fast and the transmission changes frequently when it shouldn't.

Yesterday I changed the transmission fluid. The transmission man suggested the problem could be the throttle control.

I am serching for ideas to get this great vehicle back as it should be.
Any ideas?
Thanks

 

Start by cleaning you Throttle Body, That is a good start. No codes No noises??

And stop replacing something that is new(Coil Packs). Try somewhere else first.

Also are you losing water?

 

I am loosing some water. The code's always refer back to a cylinder missing. I tried the ignition switch test I read about on here, and I am not getting a code.

 

O2 sensors and bench flow/clean Injectors.. o2 will trim fuel, but can only adjust pulse on a bank.. not individual Injectors.. if one or more is clogged up or not flowing right, you could be leaning out the corresponding cylinder, or the opposite; fattening the trim..

Either way, based on age alone (if they are oe), those o2s need swapping..

Edited to add: inspect each plug.. they will tell the true story of each cylinders health.. a leak down might not be a bad idea either.

 

Check the cat. If the No 8 plug is fouled that means the cat is shot. Any excessive particulate build up on No 8?

 

dont waste your money anywhere else. You have a blown head or head gasket.
I just spent over 5 months and hunderds of dollars on trying to fix my CEL for Random Misfire, Cylinder 4 misfire, Lean Bank1, and a couple more. You are losing water to the inside of the block, its burning with the air fuel mixture and creating a lean/miss for the cylinder.

Go have a compression test done before you buy any other part. That will tell you right off the bat the same thing i just told you.

 

I was losing a antifreeze for years and tried everything to figure it out except to check for a bad head gasket or head. was running great for years with only a loss of coolant every week. there was never a sign other than that pointing to heads until I got the misfiring from cylinder 5 this year. changed plugs, coils and two weeks later it came back. my heads were warp so definatly look into compression test first.


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I am changing my head gaskets myslef and im afraid my heads are warped. I have no way of telling but to put em back in and see how she runs.

 

Use Copper Head Gaskets then? (might be more expensive but it might be worth it if your head is a little wavy)

 

havent thought about that, what are the perks of copper gasktes, how would it effect a warped head?