A little help please, misfires.

[SarTech]

Hello all.
I have a 2002, X5, 3.0l, manual trans,165K miles. I purchased the car used with about 120K on it, Im the second owner.
Last month I had the thermostat go bad, engine would never warm up.
I replace thermostat, water pump and fan clutch.

Shortly after I got a Service Engine Soon (SES) light with codes, P1351, P0304, P0302, P0306, P0303 and P0301, all misfire codes.

I thought that I might have gotten some bad gas. Put in some Sea Foam cleaner, reset codes , all was well for a a couple trips in to town (about 40 miles round trip)
I got the SES again and basically the same codes.

Checked the spark plugs, found that they were very worn. Replace, reset codes.
Again, all was good for a trip or two into town.
Then SES, with P1342 and P1351 codes (Misfire during start and misfire cyl #5 with fuel cut-off)

Swopped #5 coil and #3 coil, reset codes.
Drove into town, on the way home SES with 1351 and 1345 codes. (misfire cyl #2 and #5 w/ fuel cut-off)
Since I had the parts any way I replace the Crank Case Vent valve and hoses.

On the way in to town SES with 1351 code. Reset codes, On another day went into town, on the way back home SES with 1351, 1349, 1345 and P0300 codes.
Replaced all coils, reset codes.

Drove into town, cars running very well, thinking I got this fixed. On the way back home bam! SES!!! with 1351, 1349, 1345 P0300.

What now? any suggestions?
The fuel pump and fuel filter has been replace about 40K miles ago.
Sure would appreciate any help.
Thanks.