Hey guys the past cuple days my truck cant idle that well it keep idle till its warmed up then it starts getting bad and almost dying like if i sit at a light it will start to die but if i shift up to a diff gear it will jump up to 750 rpms for a few second then starts to die agian and it smells like gas horribly. The reason i think it might be the plenum is that if i drive it kind of hard it burns oil at the next start up but when i baby it it dont burn oil at the start up. Then anthor reason is the spark plug on the rear cylinder on the passnger side closeset to the fire wall it always gets black and oil gunk built up on it with in a few hundard miles and i dont know why its doin that. Now i know both o2s are bad but they have been bad awhile and havnt had this problem thanks any info would help

 

have you looked down the tb??... a bad iac can make poor idle.... but the spark plug going bad sound like a bad plenum..( what im think it like a big vac leak and sum time wost when cold)..

 

yeq maybe. Its freezing cold here and i tried looking down there didnt think i say any oil

 

If your spark plugs get oil on there, it can only be one of two things. Either your piston rings are shot and oil is getting past the rings, or oil is seeping down into the cylinder well somehow. Do you see any oil around the cylinder area?

 

the fact that it idles ok when cold and lousy when warm could point to your o2's. when the truck is cold its in open loop, ignoring o2's, and then when its gets warmed up it goes to closed loop and the pcm uses the 02 settings to adjust fuel.

if one plug is fouled out, then you likely also have a problem on that cylinder. if its oily, then its probably either plenum, or valve seal, or rings. check and see if you think the fouling is oil or gas. it could also be a bad injector, dumping gas in that one cylinder. replacing that one plug might be a temporary improvement.

 

Yea thats kinda what i tought about the o2s but theyve been bad for awhile and i never had this problem unless there getting worse. But just today it started dieing before it got warmed up.