Hey guys, kind of stumped here and would like to get some suggestions before I order parts that may not be needed. Truck is a 2002 Dodge Ram 4.7

my truck had been running perfectly fine, then one morning I started my truck and it had a horrible misfire on cylinders 1 and 2. Well I went ahead and put a couple new spark plugs in those cylinders and it ran perfectly fine again... until about 100 miles later it happened again. This time I changed the sparks plugs but it did not fix the issue. I was able to get the truck back home but it definitely had no spark on those cylinders. It stalled every time I let off the gas.

I figured it could be -coil packs, injectors, maybe the crankshaft and camshaft sensors? I have no idea. Any input would be great. Thanks guys and possibly gals!

 

What are you driving? What engine?

 

-HeyYou

just updated my post! Can’t believe I forgot to put that in.

 

Does the engine make any rude noises while running? For whatever reason, the 4.7's seem to like to spit out rocker arms.....

 

Nope there’s no noises, never has been. Everyone I speak to is telling me it’s the head gasket but that makes no sense since the misfire is on two cylinders on opposite sides.

 

How many miles on it? I'm with HeyYou... it might have spit out some rockers. Been down that road.... Drove to work, no issues. Went to start it when leaving and had a misfire. Found cylinder five rocker laying there when I pulled the valve cover. A lifter had seized. It had around 315K on it at the time. https://dodgeforum.com/forum/2nd-gen...e-issue-4.html

Pull the valve covers, see what you find.

 

The link you sent me was for a 2nd gen Dodge Ram with over 300k miles. My Dodge Ram is a 3rd gen with 130k miles, one owner, and meticulously maintained. There was never any ticking or unusual noises beforehand and I recently replaced my my valve cover gaskets. When I had them off I checked everything and it was square in there. I’m fairly certain it’s not the rockers and rather fuel or spark related. Even with the misfires it does not have pinging/ticking or abnormal noises other than a more prominent belt squeak.

 

Try swapping the coils on 1 and 3. See if that misfire moves. If it doesn't, try swapping the injectors, test again. You also want to verify the coil is actually firing the plug, and the PCM is pulsing the injector......

 

Actually, it's a 2nd gen 2003 Dakota.... the one in my sig. But I get your point. With 130k and good maintenance, your lifters should still be good.

 

okay so I swapped the coil packs around and it didn’t change anything. But here’s another thing to consider, I have a high flow catalytic converter. Months ago I had a strange pop noise on startup followed by a low efficiency code for the cat but the truck ran perfectly fine. Could it be possible that the aftermarket cat is completely clogged?

edit: forgot to mention.. before I touched anything, I checked the codes and now I gained a misfire on cylinder 4. Previously it was only 1 and 2 since the start of this problem.