Andrew315

I was driving my truck (93 5.8 E4OD) to work a little while back when out of nowhere, it started running rough at idle. Still has all the power in the world at part throttle (relatively). It came to the point where it will barely run at a stop unless I hold it right above 1000 rpm. I replaced my manifold gasket probably two weeks prior. And in the process, I rubberized my vacuum system. I know it's running rich by the smell of fuel from the exhaust. And not once has my CEL come on while driving, but I pulled codes and got these:
KOEO
334

CM
334
Yes it displayed 334 twice then the single flash and 334 two more times.
KOER
173
334
129
632 I forgot to cycle my OD.

Now I've looked into them separately but could the evp be causing the problem I'm having? Also how about the map code on the KOER test? I just don't want to start throwing parts at it in hopes of fixing it. Just need a place to start really.

sdmartin65

If the EGR isn't completely closing at idle that might explain the code and idle problems. Always solve KOEO codes first then go to KOER if there are any after fixing KOEO.

Andrew315

Not only was the egr just not closing but stuck fully open. I just overlooked it even though I should have just looked into the evp sensor code. Jarred it loose with a screwdriver and expecting I will have to buy a new one soon. I really don't want to fork over the $90 just yet. I have to pay rent this paycheck.