07 Ram 1500 5.7L, Intermittent P0300 w/ other codes

[Frankenstein]

Current codes with the truck right now are P0405 (EGR Sensor "A" Circuit Low) and P0038 (O2 Sensor 1/2 Heater Circuit High.)

Seems when the misfire occurs the codes that pop up are the ones above also including P1129 (Closed loop fueling not achieved,) P0300 (Random misfire,) P0152 (O2 Sensor 2/1 Circuit High.) Misfire occurs on cylinders 2, 4, 6 and 8 as per scan tool but only when under load. Seems as if the issue is more common now that I eliminated the exhaust leak from the drivers side exhaust manifold to catalytic converter flange.

Personally I'm thinking the EGR code or O2 sensor codes are playing a part in this but unfortunately this is over my head. Any thoughts?

 

[Gur88]

Could be bank 2 sensor 1 is giving bad fuel mix ratio info to ecm, putting it out of trim spec causing lean misses on the even bank. Do you have an obd2 scanner?

Edit: after rereading I see you do, go into the engine monitoring and look at your short term and long term fuel trim when it's missing. I'm willing to bet it's going to show -20% or so.

 

[Frankenstein]

Could be bank 2 sensor 1 is giving bad fuel mix ratio info to ecm, putting it out of trim spec causing lean misses on the even bank. Do you have an obd2 scanner?

Edit: after rereading I see you do, go into the engine monitoring and look at your short term and long term fuel trim when it's missing. I'm willing to bet it's going to show -20% or so.

Unfortunately I only have a simple scanner from Canadian Tire (Innova 3100j) and does not show fuel trim. Just shows O2 voltages. Figured I'd just throw the $49 for the O2 sensor at it and see what happens, either way it needs to be replaced. I'll let you know.