2003 Yukon Rough Idle

[spudly]

Hopefully someone has an answer for me!
My 2003 Yukon runs rough at idle and even dies. The other problem is that the problem is intermittent (the worst kind of all automotive problems...) but the problem is becomming more consistent. It has given me a MAF trouble code and Lean Banks 1&2 codes.

I've cleaned the throttle body (as suggested in another posting) but no change. I've changed out the MAF sensor to a Granetelli one in hopes that the MAF error may be connected to the AirRaid intake and TB spacer allowing more air but no change.

Any ideas? (other than going back to stock which is my next option...)

Thanks in advance!

[maxwedge]

Sounds like air is entering the engine behind the maf and not being sensed ,of course this drives the mixture to lean. Bad tb gasket, vacuum leaks and so on. Yes I'd go back to square one also.

[spudly]

Originally Posted by maxwedge

Sounds like air is entering the engine behind the maf and not being sensed ,of course this drives the mixture to lean. Bad tb gasket, vacuum leaks and so on. Yes I'd go back to square one also.

Thanks, I was a bit concerned about the cheaply made paper gasket that came with the Poweraid TB spacer so looks like I'll try to spray a little carb cleaner around it and see if the idle cleans up- that'll help narrow down the possibilities. I'll also see if I can get a better TB gasket to go between the TB and the spacer. I wonder if this is a known problem with AirRaid?

[spudly]

Okay, I've tried going back to stock, but no good. I've cleaned the throttle body, and checked for leaks where air could possibly be getting in behind the MAF. Nothing seems to be working. If it were a bit more consistent I'd stand a better chance at this, but it's not. Sometimes it idles high, sometimes it idles low, sometimes it idles just right. Off idle there is no hesistation at all but on idle it stutters and dies. Any more ideas?

[maxwedge]

Are there any codes now, suggest confirming good fuel pressure and try disconnecting the egr, and/or cleaning the pointle, the lean code is the clue here.

[GMMerlin]

Check the intake gasket at the head...possible vacum leak

[spudly]

It sounds just like an EGR (stuttering, surging, rough idle...)- just like the EGR were letting too much exhaust gas through. So... where is the dang thing? I've looked everywhere and can't find one. I've even looked for a part number and all the online stores are saying one is not available. I have a 2003 with the 5.3L. I'm sitting on about 80k miles so I know its about time for a cleaning.
As for the intake gasket, I haven't ruled that out either. I want to try all the simple stuff before I decide to pull the intake off!
Thanks for all your help, this is just about to drive me nuts!

[maxwedge]

Hey, maybe there is no egr, I am not sure, I'll pm GMmerlin he's the guy on top of these.

[Stealx]

Any update ? I think I have the same exact problem, very noticeable when cold, not really when it warms up

[tec5120]

coolant temp sensor located at cyl#1 in the head..............

[atlantis_my]

2002 Yukon: I changed Idle Control Valve ($140), Throttle Position Sensor ($54), and spark plugs but did not fix problem. I removed the cable to the Throttle Position Sensor and the idle became stable (this cable is next to the ICV).

Went to dealer. They measured fuel pressure and it was low. They changed fuel filter and did not improved. Then they changed fuel pump and it fixed the problem (part $500 and labor $500).

[pete3006]

Any updates on this topic? i have the same problem...changed MAF,Cleaned throttle body,changed fuel filter, Map Sensor,and had Injectors cleaned still rough idle and surge...

[maxwedge]

2 year old thread. looks like it is dead, no? Anyway I would check fuel pressure and make sure it holds when engine is shut down, 60 is around what you need key on engine off.