[Oregon Cab]

Replaced DME relay but no improvement so put old one back. New fuel filter had to blow out fuel but not terrible.... new one is clearer. Found 3 disconnected hoses, Filter box, small braided hose behind Air Flow box and large black hose (lower one from the oil filler area) to top of manifold was broken at the clamp. Amazing. Still stumbles. Changed fuel filter, cap and rotor. Starts and idles very smooth and strong but still stumbles and farts at 2900 and will not increase. Checked readings at the cht, speed and reference sensor seems to be ok. Tested all plug wires (2.9-3.0) and coil wire was corroded at distributor plug and could not read! Got a new connector and cleaned screw-ins. Wire checked out without caps. Will replace spark plugs, reset dist cap and wires and test Air flow meter for ohms while pushing flapper. My tech suggests I don't dismantle it.

Assumptions: 1. Starts and idles great to 2500 then hits the wall stumbles and farts. Vacuum leaks would show at idle. 2. Backfire at the tail and stumbling under a load indicates a firing and timing issue or fuel. Caused me to double check wires and replace cap and rotor. Plugs next.

Seems like when I had my 74 tii, this kind of issue was always in the timing or burnt parts. I am surprised these symptoms are such a mystery.