All the normal maintanace things.
Did you change plugs, wires, and ignition cap?
Check all small vacuum hoses carfully for cracks and leaks?
Clean or check MAF sensor if you have one?
Start you truck at night and look closely at the ignition wires
coil and cap. See any light show?
oops, sorry, I should have said --- it had a complete tune up about
6 months ago and it ran better than ever.........until the idle problem
started a month ago. So some of the things you mentioned I have
to assume were covered. But yeah, could have developed a vacuum
leak since then.
I remember someone saying they had to "reset the codes" or
something similar. How are they reset ?? ( eg, after changing the
battery I think it resets itself by just driving it or letting it idle
long time )
Check all the vacuum lines: PCV, EGR, CANP, Climate control. You'll
find them all neatly illustrated on the emissions calibration sticker
under the hood. What you are experiencing is 10-15 seconds of fast
idle, where the car's computer sends the signal to the IAC to allow the
engine to rev at higher rpms to warm it up. Then the signal stops to
allow the engine to idle normally, except in your case where you have
something gone awry it doesn't. I'm pretty sure that's it in laymen's
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