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01 lesabre suddenly running rough in the cold

12-16-2010, 02:04 AM
It has gotten really really cold here in MA these last couple days. Yesterday when I started the car it had a brand new loud rough rumbling sound which was really only apparent from within the vehicle. Outside and in the engine bay things still sounded like they usually do. This roughness continues at a standstill, while driving, and in all gears. It follows the RPMs. There is still plenty of power. When the car is COMPLETELY warm it finally goes away, so I'm thinking it's something near the periphery of the motor that takes a while for the warmth to reach. Are these rough-when-cold symptoms typical of a particular component? There are no codes.

A little history: 107k on the car. Did the upper and lower intake manifold gaskets, as well as the plugs and wires and a cursory throttle body cleaning, 2500 miles ago to cure their oil and coolant leaks (only now I have an even worse oil leak which I believe may be the head gasket(s).) Since that "repair" the idle has been ever so slightly rougher than before, but this new roughness is brand spanking new. (So maybe it's a vac leak that is now exagerrated by the cold? I had sprayed all around looking for this leak before to no avail.) Just did the first oil change since my UIM/LIM "fix" and the dirty oil looked the same as it always had.

12-16-2010, 01:53 PM
From here there is no way to accurately diagnose a vague noise as described. Have someone listen to this onsite for a proper analysis. Maybe the exhaust is grounding to the body?

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