bad miss fire

[keith300]

hello i have a 1991 4 banger with the dual spark. i was driveing the truck on the freeway yesterday going up some steep grades and the truck was running like sh** hardly any power at all had to be in third at around 3500 rpm to make up (driven this part of freeway many times truck normaly just cruises up) so i pulled of tuck stumbling and hole truck shaking. so limped it home pulled all the spark plugs and the number 2 cylinders from spark plugs looked likes this.
http://s81.photobucket.com/albums/j232/keithison/?action=view&current=sparkplug.jpg sorry for bad pic off cell phone
the rest of the plugs looked OK but the almost had a greenish yellowish tone to them. the plugs are the cheap copper champion plugs plug have about 4000 miles on them.
any help of what might of caused this would be greatly appreciated

 

[dangerranger83]

Might be just a bad plug from the factory. It happened to my stepdad a few years back on his motor home. He replaced it and never had the problem happen again. But from the looks of it you had a dead cylinder while trying to climb a hill in a 4 banger, that must have been fun.

 

[keith300]

UPDATE: intalled 2 new spark plugs still runs like crap. thinking maybe be a broke piston ring? maybe collapsed valve lifter i don't what do you guys think? truck only has 120000 miles on it though

 

[351rangerxxx]

find someone with a baroscope to look into the cylinder

 

[dangerranger83]

Could be anything such as a bad coil pack, bad injectors, connection to those things but ya a baroscope into the cylinder with the bad plug might help first.