I am at my whits end with this truck. It is 2007 Ram 1500 with 5.7 Hemi. I have replaced timing chain, tensioners, both heads (remanufactured heads), just to have the transmission go out so it is has been replaced as well. All work done in past month. Picked it up from transmission shop yesterday got $20 worth of gas because gas light was on and drove it home. It did fine the entire way. Backed up in driveway and started idling rough, then check engine light came on. Drove it back to my shop and put scan tool on it. Getting P0300 code (random/muliple cylinder misfire) and P1416 (AIR Sys Bank1) code. I cleared codes and drove it and it was actually a little better, still has miss but when in overdrive wasn't having the hesitation at load (hills, etc). Got back to shop and check engine light came on again. Put scan tool on it and same codes. Still missing at idle. I see where people have had issues with bad gas but I am getting some different codes than they are. Any help would be appreciated.

 

My truck is doing the same thing. I got a p0300 code one day check fuel replaced o2 sensors check for vacuum leaks. Then one day while I was driving home from work it finally switched to a p0304 code. So I was in the middle of replacing the coil packs and spark plugs when cylinder 8 spark plug broke. Had it to the shop and they was unable to get the plug out. The previous owner never replaced the spark plugs and it had 144,000 on when i got it. So now i am in the process of changing the heads. I would say look at the coil packs and plugs and also the injectors.

 

What was the issue that caused the timing chain and head to be replaced? I would start to think either the PCM itself or bad wiring in the harness. I don't have an MDS system. If you have an MDS failure on a cylinder then it can act as a misfire. I am not impressed with the MDS system. Too much added complications for the MPG gains. The concept is nice to deactivate cylinders when you don't need to power but add in all the extra parts to eliminate the compression stroke and you seem to shorten the life of the engine.

 

I broke a spark plug off and was not able to get it out. So i went ahead and put two remanufactured heads on and I checked the tensioners and found that I could push them down with my finger. I also, do not have a MSD system in my truck. I am still in the process of putting everything back together I am hoping that I have fixed the issue once i get it going again.

 

I’m having the same issue on my 2006 1500 (v6 3.7). It has a rough idle only when at a stoplight or in park. I’ve recently had the fuel pump changed as well as a new catalytic Converter and o2 sensors and spark plugs and ignition coils. Any suggestions?