I am slowly going bonkers trying to solve this cel on my 92 f150- it does seem to lack power and seems to be going through the gas, not running hot or anything... code 41C says No HeGo switching detected - I have swapped the sensor and used an old sensor harness to test the vehicle harness, haven't checked the info side but the heater side shows power....is it as simple as the computer is not detecting input from the sensor? In which case, I need to test the wiring harness back to the computer I guess, to see if there's a break in the circuit....if it's not detecting the sensor, is the engine running in a default mode that would be kind of low performance?

I've checked extensively for vacuum leaks in case it really is a lean situation owing to leaks - replaced some hoses and replaced pcv valve. Removed and cleaned egr - could not see the orifice some books refer to to clean (this model has the transducer on top and below the body there's holes in the bottom) - didn't know you shouldn't use solvent on it, squirted some deep creep in there cleaned some rust and buildup around it, checked its range of modem and it all seemed ok but then got the code 34 which I think means voltage out of range - when I removed the transducer it seemed ok all I did was gently push the shaft up and down through its motion range... vacuum applied to the body seemed to work all right I think it held vacuum, some reading I've done says that's ok some valves should hold, others not.

Any thoughts on this? Kind of frustrating I've added another problem by the look of it, unless the egr comes good by itself...