2001 Isuzu Rodeo Question Hesitations, sluggish on accelerat

The car hesitates, gets sluggish, will jerk from getting power back and loosing it again on acceleration. Intermitent. I have a code for p0300 multiple cylinder misfire.

This is what I have done:

1. Had code for p0303 changed all plugs (Bosh) got better for a few weeks, now it is doing it again. Ckecked cables by unpluging and checking for obvious misfire. Cables seem ok

2. Had a code for bad cam sensor - Replaced it code gone, still have problem.

3. Had transmission fluid low code - had filter and fluid changed at Mr. Transmission fuel filter too- code gone.

Did some research online and came up with following
4. Bad gas(did 2 treatments of gas treatment 1 (stabi)l 1 specific water treatment);

5. Cracked head or head gasket, but no evidence of water when changed plugs.

6. Reference to only using spacfic OEM (Denso Plugs).
Haven't done this yet.

7. Ran into a guys account with same problem and his ended up jumped timing. So, I was thinking about changing the water pump and belt and setting time this weekend as 130000 needs to be done I think anyway. Haven't done this yet either, but if it is this the belt breaking could cause major problems. Does it fit with the code?

The only code I have now is p0300 multiple cylinder misfire.