this thing is about to drive me nuts, idle is good, can't find any air gettin in anywhere, also noticed that it won't bump the rpm's on my other 12v i can hit the pedal it'll jump up and peg out on this truck it will only hit about 1800-2100 rpm's....anything i'm overlooking now?

 

Cummin,
I had a somewhat similar problem with my 97 recently, only it came on a little more quickly than your several month observation. Long story short, turns out my problem was with a bad tank of fuel. Have you tried filling up at a different station to see if that might have any effect on your situation? I also ran some fuel system cleaner/cetane boost that helped get the "gunk" out of the system. That sure worked for me.

Steve

 

u cant rev more than 2100 rpms? then its gotta be ur timing...get that bumped to 16 degrees or as high as most places are willing to do it...some wont go higher than factory specs and some wont go higher than the "legal" limit of 14.5....alot of 12 valvers slip to below 10 over time