The last couple of days Ive noticed after running for a while, my idle comes up for no reason. It probably sits around 1000-1200 rpm. Of course the first thing I checked was the high idle solenoid, wasnt it, damn thing dont even work. Then I realized Im coming up on a fuel filter change pretty soon, but i cant see how a restricted filter would do that. I also have my timing advanced, could my advance and the cold start advance together bring my idle up? I dont know, Im stumped. Its an 86 3/4ton, j code 6.2. Thanks for any Info

No one has anything for me?

I would definitely start with a fuel filter change. Restricted fuel supply can cause all kinds of funny problems. Does it suffer from any performance problems otherwise?

No, it Runs great, starts a little cranky though first thing in the morning.....although it is winter here. But I noticed some funny things last time my filters kicked it. Ill try that first.