Hi ya'll.

Last weekend I installed Troyer Efans (install went smooth) But while I was there, I replaced the serpenteen(sp) belt, upper and lower radiator hoses and thermostat and gasket and flushed the cooling system. Then I replaced the upstream O2 sensors (the passenger side was a &itch) Whew.....

This weekend, I wanted to replace the sparkplugs so.... I took off the throttlebody, and fuel rails to change out the plugs. I installed Deso iridium TR16's gapped at .050 in place of the stock plugs. The plugs that came out looked good except for the wear on the electrode (70000 miles on original platinum plugs). While I was there, I checked all the COP's with my multimeter (ohm setting) and they all checked out. The boots looked good also. I put some diaelectric grease on the boots and reinstalled. I also checked (with ohm meter and visual) each injector and they looked good.

Now I turned my attention to the throttle body. The throttle body was greasy inside but the ports were open. I cleaned the throttle body with STP throttlebody cleaner. I also cleaned the idle control valve; (though I was not having any idle problems) I figured it would be a good idea. Put it all back together with a Plasa Booster from troyer performance.

Everything seemed ok until I fired her up. VERY ROUGH idle but will run great when put on the road. Runs as if it were brand new except for the idle. I think I messed up the idle control valve when I celeaned it. When I did my research on this site for cleaning the throttlebody, the information I got was to clean the idle control valve, but my Chilton manual say do not spray any cleaner into the working of the idle control valve as you may damage the internal workings...... Do you think this is my problem with my idle - the truck runs great in every respect but for the idle?

Oh, could some one look at their 5.4 and let me know if the red vacuum line attaches to the canister in the drivers side fuel rail and that the green vacuum line attaches to the egr valve. Also, why does the line that runs from the top of the throttlebody to the gizmo on the driversside firewall above the brake booster have the "GAS LINE" lable on it when there is no gas that flow through it?

Thanks for reading and any help to my questions

God bless

Jeff

2000 Expedition XLT 4X4
5.4L 70000 miles

 

I cleaned the IAC on my 4.6 and have had no problems. I would look for a vacuum leak or maybe check the throttle body gasket. Sounds like you may have a leak of some sort. Not saying it couldn't be the IAC but I would start with the other stuff first.

Good luck!

 

I filled up the IAC with carb cleaner and let it set in there for a while to clean it when I did mine. I don't think you damaged it by using cleaner on it. It could be possible, but I would look for simpler things first. Did you plug in the MAF connector? All the vacuum hoses connected? I have made some simple mistakes like this before that will throw everything out of wack.

 

I have read posts where guys have had trouble after cleaning the IAC. They recommended that you just change it out all together. If it is giving no probs then just leave it alone. There's a guy on Ebay that sells IAC's for $15 a pop so check that out.

 

Thanks for all the replys - I am going to double check everything then if that doesn't work, replace the IAC. Thanks again

Jeff

 

I fixed the idle problem. I had the green vacuum hose going to the FPRC and the red vacuum hose going to EGR. The vacuum diagram in my Chilton manual show they are switched. I switched them and VARRROOOOOOOM! I guess my idle air control valve is OK. Thanks for all your help.

Jeff

 

iv been cleaning my MAF and IAC for 9 years and its never given me problems... and i clean it about ever 6 months... i guess they just dont make things like they use to

 

It will start but will stall out unless you floor it and as I have learned it's called "hunting" for an idle, racing and just about stalling out. Check Engine light is on and also there is this whirring sound. Can anybody help???????