Several issues with 97

[elt]

I have a 97 Yukon. It idles very high, popped misfire code on cylinder 6. I am in process of changing wires and plugs. Popped code for over rev. Any ideas what would cause that?

 

[laredo1307]

Make sure and change the cap and rotor too. I recommend sticking with AC Delco parts. I learned the hard way on this one.

 

[SunlitComet]

What code for over revving? idling high is because the IAC valve maybe controlling idle high or you have a possible vacuum leak somewhere.

 

[elt]

I will definitely look for vacuum leak, my brakes are acting like the power booster is out.... So vacuum could definitely be the problem. I do not remember the code, had it read at parts store. I will be going back tomorrow so I will post the code then. I only use ac delco as I learned that lesson as well. For info at idle it is at 17000 rpm

 

[elt]

Well it is snowing today but i have been trying to locate a vacuum leak. No luck so far. I did pull the vacuum line from the brake booster and the engine reved higher. Strong vacuum at the booster.

 

[SunlitComet]

what about when you plug the line to the booster? do it run normally at that point?

 

[elt]

No plugged in it still idles high, with my finger over it still idle high.

 

[God]

what kind of performance engine do you have to be idling at 17,000 rpm?

 

[SunlitComet]

One that not even God can comprehend

---------- Post added at 02:07 PM ---------- Previous post was at 01:54 PM ----------

Then excuse the booster for now. How about are you probing for vacuum leaks? Ensure the grounds on the thermostat housing are clean and undamaged and try resetting your IAC valve by turning the igniton on for 5 seconds then off for 10 seconds. Restart engine and see what happens.

 

[laredo1307]

"what kind of performance engine do you have to be idling at 17,000 rpm? "

Formula 1

 

[elt]

Sorry on my phone and didnt notice the extra zero! I am going to clean the idle air control valve and see what happens.

 

[kcb37]

What I would suggest is google/youtube automotive or evap smoke machine.
Probably don't want to buy one, but their are quite a few DIY at your own risk kinda deal.

If you do evap you need to understand the professional machines are setup (good ones) to run off of Nitrogen, or CO2. This does not put air into the gas tank making it more volatile.

 

[elt]

I finally had time to work on the Yukon again. I pulled the IAC and it was very dirty. I decided to pull the throttle body as well and it was dirty as well. After cleaning everything and replacing she idles much lower. Running better with new plugs and wires as well. on to the brake booster.