Hey all, Ive been using this forum for quite some time n ow and figured I might as well join it. I have a few problems with my 93 with 4.9L as far as codes go. I have had the truck for about a year and its time for the dreaded NJ inspection. The check engine light has been on pretty much since I got it. The codes are 22. 81. and 99. I replaced the MAP sensor along with the Idle Control Valve(needed to be replaced), full tune up and replaced the vacuum canister(coffee can), all vacuum lines, full exhaust from manifold back and O2 sensor. These codes are driving me nuts and would appreciate any help someone has to offer. I have tried to erase codes several times but the light comes on as soon as it goes into closed loop.

 

What erase procedure are you following? Where are the codes, KOER, KOEO, or in continuos memory? I know it sounds like I'm jacking you around, codes are codes ,right? It just helps.

 

KOEO code 12. KOER ran other codes. I tried to erase codes by disconnecting negative cable from 10 minutes anywhere to overnight. I even tried with headlight switch on and any other crazy ideas that were posted. I was able to erase code 12 by pulling jumper wire off while testing but 22, 81, and 99 wont go away. I cant even find out what makes these codes come up because the explanation is vague. If it said TPS, than it would be an issue with TPS and thats easy to figure out because it leads you in that area. I dont even care about the continuous memory coeds as long as I can get the check engine light to go out and not affect the drivablity. The truck runs great with no issues at all. Just want to get light out so I can pass inspection.

 

All codes have something to do with either RPM or air management. I would double check and make sure there are no vacuum leaks anywhere. If satisfied that is OK, then look at all the black wires where they attach to the body, engine or any type of metal. The black colored wires are for ground, perhaps the same ground connection is affecting the IAC (two codes for RPM) the MAP sensor code 22. The 99 code (idle not learned) again could be an electrical glitch.

When we feel the engine is running great and have the CEL on, well I know how you feel. Keep with it and by the way, I like your erase procedure (turning off the self test during the test mode), thats how we were instructed to erase codes. I offer no comment on the other procedures. Good luck and stay with it, keep us informed.