Trouble with engine
1995 PSD, scanned for rough running, indicated the fuel air metering auxiliary emissions control. Also indicated No DTC definition found, refer to service manual. OK, truck starts, runs rough, does not respond to throttle, engine check light on, sometimes will run good, intermittently check engine light goes off, then back on and rough running continues. What is fuel air metering Auxiliary Emissions control, where is it, what does it do, how can I fix it. Repairs so far, replaced wiring under valve cover on cyl 6 & 8, new valve cover gasket, complete injector/glow plug fuel wiring harnass on top of engine. Please, somebody talk to me, I'm going nuts here!