05 Dodge Magnum 3.5L. P0300 only at hot idle.

Hi guys. Here in CA.
05 Dodge Magnum 3.5l, V6, 100k miles, ck eng light comes on only at warm idle. P0300. Won't pass smog.
Have had this issue for years intermittently.
Starts fine, cold idles fine, drives beautifully. However at hot idle, 580 - 630 rpm it triggers p0300.
With a scan tool I see minor misfires on bank 1 and High LTFT on bank 2.
RECENT:
failed smog for p0300 and p0108. Light came on at smog shop. I replaced MAP sensor, completed drive cycle, light off. Went back, no light. P0300 came back on idling in smog shop again. 2nd fail.
REPAIRS:
2k ago I replaced the front o2's, plugs, coils. This time I replaced the injectors, front O2's again (NTK)and swapped the coils and plugs and O2's from bank 1 to bank 2, cleaned Throttle body. This made no difference.
Drives great in all conditions, buuuut hot idles rough, with high LTFT bank 2 only +25%,  with cylinder misfires on bank 1. Above 750 or 800rpm misfires cease but u can feel the idle is a lil rough still.
DETECTIVE work so far:
Smoke tested Intake. Vacuum tested intake, smoke tested exhaust. Front 02's switching as expected and both rears steady 600-800mv.
MUST KNOWS:
Chrysler released a TSB on these engines for P0300. Chargers, Magnums and Chrysler 300's shared this engine. The exhaust valves can accumulate carbon buildup if not occasionally driver over 3500rpm. The fix is to manually rotate the valves, install new keepers and dump MOPAR cleaner into the intake.
This is a MAP engine. No MAF sensor.

Questions:
Time for a pro to diagnose? I was feeling burned at the smog shop so decided to tackle this myself with a scanner and Pauls videos. I have no electrical experience, but I'm a tryer. I am also out of enthusiasm, lol.
Happy New Year everyone and thanks. 
 

Hey GerryMag! Thanks for all the history and testing information. Definitely helps when providing assistance.

Would you be able to provide the short and long term fuel trims after a cold start, and with the engine warmed up? At idle and 2,500 RPM would be helpful.

When you say misfires on bank one, how are you monitoring that? Could you provide the specific misfire counts on each cylinder during a hot idle?

I've seen that TSB before, but I can't say I've ever run into one of these engines that needed the whole 'manually rotate the valves' thing. I'd suggest at least getting a look at the exhaust valves themselves before going to all that trouble. A borescope in the cylinder with the exhaust valves at full lift could give you a decent visual of the exhaust valves:

www.amazon.com/DEPSTECH-Industrial-Inspe...-Rigid/dp/B0928Q3T42

Hi Tyler. I'm using an XTool D7 bidirectional scanner. (learning to use that is). Thanks for the Boroscope tip. I failed to do a compression test before I reassembled the upper intake. If I dig back down there I will scope the exhaust valves. The intake valves are clean as a whistle however.

Startup Cold Idle:
RPM: 1109 B1ST: -12.70 B1LT: 5.86 B2ST: -13.9 B2LT: 25.19
Warm Idle:
RPM: 591 B1ST: -4.89 B1LT: 5.86 B2ST: -4.89 B2LT: 25.19
Warm at 2500rpm:
RPM: 2505 B1ST: 1.75 B1LT: 4.10 B2ST: 2.14 B2LT: 16.41

Misfires:
At 598 rpm warm idle I see the following
Cyl 1 Misfire counter 56
Cyl 3 Misfire counter 45
Cyl 5 Misfire counter 54.
Interestingly, this scanner shows Injector Pulse Width for Cyl 1 and Cyl 2 only- however I believe this is misnamed and should be Bank 1 and Bank 2.
At this rpm, PW1 is 2104 and PW2 is 2648

Thanks for getting back to me with the data. 

The skewed trims being opposite of the misfiring back could be indicative of a valve timing problem. Specifically on bank one. The PCM wouldn't pick up on it in this case because the (only) camshaft position sensor is on bank two.

I'd be very tempted to do a compression check next. If not all cylinders, than at least one on each bank. Problem is, I believe the upper intake plenum covers bank one on this engine! You'll have to decide if that's worth it to you or not. You could go straight for the timing covers, but that's significantly more work, IMO.

Relative compression testing is an option. But, unless you already own and use a scope, doing so might be counterproductive. Listening to the engine during clear flood cranking is another option, but picking out the difference in cranking cadence can be tough if you don't know what to listen for. Compression testing and visual inspection is more conclusive.

Thanks Tyler. Btw, I was just reviewing the freeze frame data from the last P0300 triggered. My scanner reports RPM at 161! This isnt right as I was sitting in it idling at the time. I pulled out an old scanner (Foxwell) and checked FF with that and same thing, 161RPM.

I looked at my older data and see RPMs low several times when P0300 was triggered. Could this be an anomaly or a clue?

At 80K, I had a shop replace the timing belt and water pump for maintenance. I had P0300 intermittently before that and since - didnt seem to matter. Of course its gotten worse since then. 4 years ago, I replaced the EGR and Purge valves and that got it through a smog check (parts guessing - no good reason)

If I keep the rpms slightly high at a stop or idle, I can avoid triggering P0300, however thats not how it works at a smog shop, lol.
Is it possible the valve issue would only be a problem at low, hot idle?

Based on this, what would your likely next move be?
Im prepared to do a compression test and check the exhaust valves.
I'm also prepared to take the car for a shop Diagnosis, reluctantly. Would the right tech, perhaps with a scope, likely find the gremlin?
Thanks for your help.

Quick addendum>
My scanner is showing a PID called "Cam Crank Difference". On the 2nd last triggering of PO300, It read (-1.5 degrees). Is that a clue regarding the possible valve timing issue?
And, you're right, one Cam sensor on Bank 2, drivers side, only!

Couple of pics related to the details. First pic shows the FF date when P0300 triggered last time on old Foxwell scanner.(161rpm)
Next few pics are of a recording taken while driving around steady.
notice the big jump in LTFT between readings taken at similar rpms and road speed on the flat.
Last pic is same drive, showing just rpms and B2 ft's. 

Is any other data likely to provide any more clues for u guys? Thanks again Tyler and anyone else who gets sucked into this thread