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Old 12-04-2007, 11:25 AM   #1
alamantia
 
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Join Date: May 2006
Location: Midland Park, NJ
Posts: 1,389
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Rough Idle Once Warm?

Last year I bought a 1992 K1500 Blazer and drove it all winter and gave it a tune up in the spring when the ignition module went. When i first bought it I noticed it idled a little rough but figured it was just old at 160,000k and the rings were worn. When the ignition modlule went I replaced the module, cap, rotor, wires and plugs along with Air cleaner and PCV valve, belts hoses and thermostat & radiator. Still idles rough. Fuel pump went last summer, replaced that along with the filter. Put a new altenator and battery in it a few weeks ago. All said and done, still idles rough. Whatever, its old and the rings are prolly shot right? I notice that when i start it in the morning now that its cold out, it fires right up like a champ and goes straight to high idle, once it comes down off of high idle to normal idle the temp gauge is showing 120-140 degrees, it idles supurb, i mean like new, i cant believe how well it idles, not a shake stumble, nothing, now I know it is capeable of ideling like it should, once it goes up to 180 (180 stat) it idles like **** again, WTF? Should I take the IAC and EGR valves out and clean them with Carb cleaner? I could see if the heat is causeing the engine to expand and causing a vaccum leak between the intake runner and the head but I figured if it heats up any leak would close, not open? any ideas? Why does it idle fine when cold and like crap when hot? What causes that? Timing?
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Last edited by alamantia; 12-04-2007 at 02:29 PM.
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