K1500 Fast Idle Pblm

The truck is a 1992 K1500 w/ 4.3l v6 5sp manual. The truck remains at high idle (1900 RPM) even when it is warmed up. If i shut the engine off, then restart it (when parked, after a reasonable drive to warm it
up) I get a more normal idle speed of around 900 RPM. This is odd. The check engine light illuminates upon starting and will go out after I get on the high way and am traveling at highway speeds. It comes on again when I let up on the throttle to exit the highway. I've checked for vaccum leaks but can't find any around the TBI body. I'm thinking I may need to change the base gasket on the TBI since I've never done it and it could be getting old and cracked. If it were cracked I would suspect that I'd have a high idle all the time rather than have the vehicle go to a low idle if I restart it after it's warm. I'd be interested to know if any body else has dealt with this.
re5513
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I had a similar problem, replacing the TBI base gasket solved it, I would recommend doing this as it is inexpensive and could use changing even if it doesn't solve your prob. My 2 cents worth......

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Sounds ALOT like the IAC (Idle Air Control) is shot. First thing to do is pull the codes from the ECM and see what is triggering the SES light.
http://www.syty.org/old/d&e.html#chk
Doc
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. . ==========Jul 28, 2004, 6:50pm (CDT+1) From: snipped-for-privacy@nope.com (Doc)
Sounds ALOT like the IAC (Idle Air Control) is shot.
First thing to do is pull the codes from the ECM and see what is triggering the SES light.
http://www.syty.org/old/d&e.html#chk
Doc ======================== what Doc said.
And start getting tuneups....it's hot enough out here.
~:~ Marsh ~cuts his key on....off.....on....off.....on....off on...off....on.....off....on.....off.....on....off...on and on and on and on~ ==================
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snipped-for-privacy@yahoo.com (re5513) wrote in message
Thanks for the pointers, I'll work on it and let you know how it goes. re5513
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