JJP,
This may not help, but this is how you adjust the cable.
You will need a 2" C-clamp. It can be done without it, but it's a real PITA. There are three cables to the throttle linkage. One from the pedal, one from the cruise control, and another from the transmission. The transmission cable is the lower one of the three. Before you do anything measure how far it is from the pointy end of the cable housing where the wire comes out to the black plastic block that the cable housing comes out of. If this doesn't help you will want to put it back like it was. The black plastic block is kind of cube shaped except that it has a button shaped bulge on the side away from you. This bulge is NOT the button. It is the housing for the button spring. The button is the flat side of the black bulge oposite the spring housing. This has to be pushed to release the cable housing so you can move it. That's what I use the C-clamp for. Use it to press and hold the button while you adjust the cable. Then hold the adjustment with one hand and release the C-clamp. Mess around with different settings and see what happens. If that doesn't help put it back where it was.
Actually, I think you need to go to NAPA and get a bottle of red LubeGard. Use that, not just some "transmission gunk".
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Joe George
Eureka, CA
'95 2500 CC auto 4X4,3. 54,Combo EGT/boost guage,custom switch panel,PacBrake,TST #5,DTT TC/VB,Automatic motorhome steps on both sides,Foldacover hard bed cover,Cummins chrome kit,Black steel grill guard,Front hitch receiver