99 GMC Sierra 2500 6.0L 2wd misfiring

[MRbam444]

Truck is a 99 GMC Sierra 2500 extended cab 6.0L rear wheel drive about a year old with me and has about 260,000

Mods: true dual straight pipe with cats

New ac delco spark plugs gapped at 0.062

MSD street fire spark plugs at 8 mm

 

Any how one day was cruising and got a soda and started it up and noticed it was running on 3-6 cylinders pumped the gas a bit and all 8 came back coil packs are all sparking to the wire and all the connectors are delivering power 12v

Need help with this ASAP next parts to replace will be performance coil packs then the injectors codes where

p0300-random misfire detected

P0102-maf sensor circuit low frequency

P0332-knock sensor 2 circuit low input (bank2) x2

Autozone code summary says replace all valve springs and bad valve springs will cause popping and misfire but it misfires when I start it and put it in gear and only for a minute or so until I hammer down and get all 8 back running this is a very dangerous problem for me since it's my only vehicle and I have 2 children

[txab]

For starters the recommended plug and gap has changed from original from factory. New gap is .040 per GM if your VIN matches this:

 

http://www.gm-trucks.com/forums/topic/121181-did-i-ruin-my-new-iridium-plugs/?do=findComment&comment=1079941

[rjgti]

work on rhe 102,332 codes. may be wiring related as knock wiring needs to be updated

[anumber1]

Definitely clean the maf.

 

As far as the knock sensor, the wiring is pretty delicate as are the sensors. Best to check the sensors and the wiring, especially if the vehicle is regularly subjected to wet conditions

 

Also agree that the plug gap has been updated to a much tighter gap.