Cold Engine Misfiring

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Ksulli32

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Hi guys, I have a 2005 Yukon SLT with 283,000 miles on the 5.3 Vortec. I live in Vermont so needless to say the winter has been absolutely brutal. Lately I have been having the problem of a decently rough idle when the engine is cold. It sputters and is obviously misfiring. When the engine is really cold it will show the "Class A Misfire" blinking check engine light, but all I have to do is restart the car and that goes away. Once the engine is warm it idles a little better, still rough but runs fine under load between 1500 and 3000 RPM. I've got bad valve seals so there is a little bit of oil leakage into the cylinders, so I am sure that the plugs could use a cleaning. I also have been having low idle oil pressure problems, thinking I need to replace the pump and pan gasket as read on another thread. I never had this problem in the warm weather, only when it sits outside in the 0 degree temps. Was wondering if anybody else was having this problem, is this a major issue with my engine that needs to be addressed leading to $$$ (just a poor college kid), and are there any immediate remedies that I can do to help the problem? Thanks a lot, appreciate all the help.
 
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SLCHOE

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Honestly, if you are planning on keeping this truck and thre rest of it is in good condition (suspension/driveline/ ABS, etc), just source a low miles engine (100k to 150k) from a salvage yard, go through it (rear main, front crank seal, oil pan gasket, valve cover gaskets, water pump, intake manifold gaskets, knock sensors/harness, thermostat, plugs, etc) and swap it in. You are up there in miles. Your engine sounds about done.

To verify, pull all the plugs out of it and do a cylinder by cylinder comprssion test.
 

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