I got a 93 Kenworth t800. The jake brake is intermediate. It comes on at about 1200 rpm. Also when the jake brake is on and I put it in neutral and let out the clutch, a couple seconds later it will chug a couple times then dies. IT is fine if I flip the brake switch to off. I have already replaced the switch on the clutch pedal as the dealer thought it was most likely. Anyone else got any ideas?