| 85' 4100 HT stumble and surge
I recently purchased an 85' Eldo w/ 84,000 miles and after a month of effort can't cure my last drivability problem. Symptom is an off-idle stumble (most noticed from a standing start) and low speed cruise surging (25-40mph). I have replaced: cap, rotor, ign. modual, plug wires, plugs, dist. cap harness, throttle possition sensor and harness plug, catlytic converter, exhaust resonator, and various and assundry other minor items. Most recently I have removed and cleaned the EGR twice. This effort has eliminated several other issues but still have the stumble and surge, only after the engine is at full operating temperature (i.e. >12-15 minutes drive time). Also observe erratic "Fuel Info" display with "instant" mode selected, display will rapidly indicate low single to high double didgit numbers and occasionally display various alphanumeric combinations along with intermittent lighting of the "Range" mode light or going blank for up to 1 second, also only at temperature and only when surge is present.
The car averages 18-19mpg on my commute and >22mpg average highway.
Thoughts anyone? | 
