Hello! My 2015 R/T Road and Track has a recurring P0303 code since I bought the car, and a persistent tick that is tied to engine RPM. Swapping the coil with #4 and replacing the plugs has not fixed the issue. I suspect the culprit is a failing lifter. The car runs fine, but WOT almost always triggers the light. If I drive sensibly (light foot), the light stays off for a while. Unfortunately, I work full time while going to school, so I am stuck in a research phase until I have time to pull the heads and assess the damage. At that point, I have three options:

1. Replace any damaged parts with 5.7 parts. The most surefire, safest option. However, I also have the option of deleting the MDS system. I have no problems so far with the system, and on paper it appears like a win-win. There are a lot of people who just get rid of it altogether. Is it destined to fail? Can it be fixed with the newer variant of the MDS lifters?
2. Upgrade to the 6.4 cam. I already have a buddy who is supposed to give me a 6.4 intake, so I could do both of these together. Replace the cam, upgrade the valve springs, get a tune and gain power! This is the middle ground. Again, the option of keeping or removing the MDS remains.
3. Buy a salvage 6.4 and ECM. Get the ECM flashed with my VIN, and be a lot cooler on my block. The radical solution, and I don't know all of what would be involved. Would my motor mounts, intake box, front springs carry over?
Thank you all for your time. I love the car, love modifying it and love the vroom vrooms. But right now until I finish some of what's on my plate I'm stuck in the daydream phase.

 

1. 2015 was at the tail end of the crappy lifter run. MDS itself isn't the problem like everyone thinks, or all the earlier engines that had it going back to 2005 would have this problem as well. If it turns out to be lifters, as long as the cam isn't chewed up you can replace them with the latest part number MDS lifters and carry on. Some people think a performance car shouldn't have it; the 5.7 isn't a performance engine lol and MDS does very well in the 6.4/392 (I daily drive one).
2. Make sure it's auto/MDS cam and not the manual trans/non-MDS cam. Otherwise, throw it in with some fresh MDS lifters, put Mopar 68277306AA valvesprings (upgrade springs good to .625 lift, more than enough for the 392 cam) on the heads and go. The 392 cam doesn't' require custom tuning, but it will definitely benefit from it. Since you have a 2015 you will need an unlocked PCM for any kind of custom tuning. If you decide to delete MDS, you will need the unlocked PCM and the manual trans 392 cam.
3. Externally the engines are the same and it will drop right in. Swapping PCM's isn't a requirement, but the engine harness would make your life easier to enable the SRV in the intake manifold. FYI, HPTuners can activate that in your PCM so you can run it like factory but again, need the unlocked PCM. Otherwise the SRV can be actuated with an old school rpm switch or the Tazer harness.

 

So, you're part of the camp that has no problem with MDS? The biggest problem I've read is hesitation and exhaust drone.

 

You only get drone from certain aftermarket systems. Hesitation is subjective unless there is actually something off with the throttle. There are people who claim they can feel a 5 hp difference (they can't). Don't get me wrong, I totally blame Mopar for cheaping out on an important internal part and not doing a wholesale recall on it. In the cars though it works. I can drive two states away in my SRT and as long as I don't do a whole bunch of highway shenanigans and good use of cruise where possible, I can make it there and back on one tank of gas. Trucks on the other hand it's waste of time. The 6.4 MDS in the 2500's might work better but there's a reason the 5.7's in the 2500's didn't get it; not enough grunt to make it worthwhile. My 392 will go into MDS mode and actually shift gears lol.....watched it go into MDS in 4th gear and then shift into 5th, without coming out of it. It will go into MDS up to 90 mph but if it engages below 90 you can slowly accelerate the car in 4 cyl mode up to 100 (at least until you get to a hill or something). It's a 2012 and I have about 112k miles on it. So yeah, for a daily driver car I am a fan. My truck doesn't have it and that's fine. Hellcats and stick shift cars don't have it for a reason.