Rough Idle and running VERY rich

[NOVAhoe]

So today on the way home from work my truck decided to piss me off. Its idling pretty rough, it sounds like it has a cam in it and its running extremely rich, when you stand within 5 feet of the exhaust you can smell straight fuel. Im thinking its an ignition problem, its not throwing codes either, and it seems like its ok when accelerating besides a slight stumble right off idle then its fine.

edit: Sunlit if you see this how did your truck act when your msd cap and rotor gave out on you?

 

[SunlitComet]

not a bad jusr a simple misfire. what are the odd your fuel pressure regulator diaphragm just broke? you smell or see puddle of fuel inside the throttle body past the blade?

 

[NOVAhoe]

Ill have to look at it, i can see that being an issue, when i open the hood i can smell fuel.


just looked and inside the intake is dry as a bone. Im gonna pull the plugs now and see how they look, and ill go from there. it seems like an ignition problem to me, of course i could be wrong. Although ive been right at diagnosing everything else thats been wrong with it before lol.

---------- Post added at 04:30 PM ---------- Previous post was at 03:47 PM ----------

ok plugs look perfect, no ignition wires are loose or anything. Im gonna have to look at it this week, i gotta go back to work now of course

 

[NOVAhoe]

well little update, i went to go mess with the truck this morning and it was still running rough, had a hard time starting too. So pulled all the plugs, checked the gap on them all, pulled the dist cap and cleaned all the terminals, i also cleaned the mass airflow sensor, there was what looked like grass stuck in the honey comb, dont know how that got there. So after all that it still ran like crap, i decided to take it to my parents because my stepdad has a nice scan tool. Well not even half way down my street the truck started running fine, no rough idle, no hesitation, no stumbling, nothing. So i plugged the scan tool into it and got a pending cylinder 1 misfire code, but everything else was ok, according to the scan tool.

Well after a full day of being out and driving around doing stuff, i noticed on the way home from my girlfriends house tonight it still has a slight miss every now and then when im doing 65-70. Its nothing major, just a little annoying because my truck has always ran perfect. I dont know what could be causing it, everything seems ok, and it even stopped idling rough, it idles completely normal now.

 

[M$ke]

99 Yukon runnin rough

NOVAhoe,

I'm having the exact same problem... My truck has a history of misfires on cyl #4...My mechanic is coming over tomorrow with his scanner & some other tools to determine what is wrong. I read a post where a guy had similar probes like ours at 65-70..He said he changed his crankshaft position sensor & that sputtering problem went away... I'll keep u posted & watch your posts...Maybe we can get these beasts runnin again!

M$KE

 

[Virginiabound]

Nova, it wont let me pm you.

What size tires are you running?

 

[Fishin757]

he runs 265/70/17, you need 10 or 20 posts to be able to pm ppl... maybe your timing got thrown off or your plug wires are bad? just an idea

 

[misspooh]

Today I posted the fix to your problem.

To keep it simple pull the crank shaft postion sensor and inspect for any light scratches/scrapes or abrasions of any sorts.

If there are any above present replace and shim crank shaft postion sensor and the faults your seeing will disapeer.

look at my posts.