96 7.3 Missing and low idle after warm up

[POWERSMOKIN]

same symptoms 2 days in a row.
So, i drive my truck 10 miles to school today, no problem. Come out to the parking lot after letting it sit for an hour or so, and i turn it on, drive about 50 feet, then it starts to lope idle like a muscle car with a HUGE cam and revs down to like, 300 or so.. i put my foot into it and its got like, 30 HP, cant move itself. CEL on, yada yada

Then it goes back to normal and drives another 20 feet and same thing.

This time it lasts long enough to where i can park it, open the hood, ant take a look. it sounds like only the passenger side bank is firing and its REALLY loud.

shop i took it to said there was no codes, but when they ran a diag test, the exhaust back pressure SENSOR was bad.. i unhooked it yesterday when it was running fine, and there was no change. so today when it was idling like crap, i took the sensor off, and there was no fix.

eventually it started firing normally, and it doesnt do it again... well, while im driving it.

Could this be a bad CPS? i havent replaced it in the 6K miles ive had it.

i also seafoamed the fuel bowl with 1/3 can... could this be the cause? broke my injectors?

[POWERSMOKIN]