confusing misfire

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Feb 10, 2006 | 02:32 PM

boatin2

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confusing misfire

I'm new to the whole forum thing so bear with me here. I have an 89 f250 with a 460. Once the engine warms up it starts to misfire so bad it's barely drivable. When it's cold it runs great, no miss, plenty of power. When it's warm, if I can make it into the higher rpms the misfire goes away entirely. I have replaced the ignition control module, pickup module, cap, rotor, plugs and wires. Also I set the timing to 10 degrees. I'm at a complete loss on this one. Any ideas or if anyone can tell me where to get a vacuum map for this motor I'd appreciate it

Feb 10, 2006 | 03:50 PM

Kemicalburns

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From: Bend,OR

have you pulled computer codes? when you set the timing was it with spout connector removed and 10*btdc? what kinda plugs are you using (brand)

whats your oil pressure at once its warmed up

Feb 10, 2006 | 04:19 PM

boatin2

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I did set the timing with the spout connector removed, I think its 10 BTDC. The haynes manual mentioned it being 10*BTDC but when I went to set it instead of it being a plate with several marked notches, there was just an arrow shaped tab. So I set it to the point of the tab, same place it was at before I pulled the distributor to change the pickup. I put in basic autolite plugs with the top end wires napa sells. The truck only has the stock oil pressure gauge and the needle is always sitting near the center of 'normal'. How would I go about reseting the computer in this truck? It's full of bad codes right now, I ran it with various sensors unplugged to see how it would affect the engine. I just read a similar thread where crossfiring was the problem. To prevent that do you just make sure the wires to two consecutive cylinders are not side by side?