Hey guys, I know I've seen a few of these posts but I have to ask. I recently got a check engine light for cylinder #3 misfire. I did the obvious thing and checked spark plugs (looked good) and changed the coil pack on #3. No luck. Thinking the old coil pack wasn't the issue, I put that coil on the #2 cylinder since the two are supposed to be connected. Again nothing. I don't have any unusual sounds either. If I drive easy, the engine light stays on solid and the truck seems to run fine. Once I get on it, the engine flashes and the misfire becomes obvious. 88,000+ miles, just started about a week ago. Does any of this sound familiar? Ant bright ideas. My next thought is injector but someone thought you would get a different code for that. Thanks for the help.

 

could be many things. Does your truck make any kind of lifter noise? From other posts, the most serious cause have been lifters that wore down the cam.

 

I have a similar problem with a 2011 Ram 1500 Crew Cab 4 x 4 with the 5.7 Hemi. My truck has 220,000 miles (354,000 kms) on it. My problem with the misfire and the heavy engine vibration / misfire only occurs above 4,000 rpm under rapid acceleration. AT an idle you do not know the truck is even running as it dead quiet and smooth. Performance is normal up to just over 4,000 rpm and then the **** hits the fan, the check engine light is flashing and a warning gong is sounding off. I slow down to about 1900 rpm and keep driving for about 60 seconds and the warning sound quits, the check engine light stops flashing and the vibration is then gone until the next time I accerate over 4,000 rpm. We have swapped coils, plugs etc and the problem stays with the same cylinder. It can not be the cam or the MDS system as it runs perfectly right up to 4,000 rpm. I have also been using a Lucas zinc phosphate additive for several years (and no idling) in the hopes these two items may delay the cam wear problem.I am not losing any coolant that I have noticed unless my dealership has been topping it up and not telling me. But I wondered if there could be a small crack in the cylinder head (or bad head gasket) that only opens up under the added heat of rapid acceleration and lets a tiny amount of antifreeze into the combustion chamber. Then once rpm decreases to 1900 rpm, the head cools down after a few seconds and the crack closes. My only other thought is a bad fuel injector that just can not fire that rapidly any longer.

All help is appreciated as my dealership is likely hoping to sell me a rebuild.

 

Check the valve springs on that cylinder. Might be cracked, or even broken. Don't know what style those springs are, if there is more than one in there, or what.

 

did you ever fix this problem mine is doing the same thing right now