I've read with dismay the other threads of 3.0s owners dealing with harsh idle and vibration on an otherwise excellent running engine and really finding no direct cause.
However my idle/vibration scenario is a little unique that i hope some of the seasoned Gurus might be able to throw some good suggestions my way,
My 3.0 runs great but anytime the outside temperature gets 40 F or below she will always have a harsh idle/vibration while stopped in park, even after the engine has warmed. When I hit the accelerator --gone- -and the engine runs smooth as butter otherwise. Yesterday the temperature got up to a wonderful 68 F and while at a stop the engine idle is normal and no vibrations. This has been the scenario for the past two years. But come Spring and Summer the vibration is non-existent until the cooler temps of late Fall and winter.
There are no codes and I've done quite a bit of usual maintenance that one would think would have addressed this issue: rebuilt my DISA (with new O ring), new intake elbow, cleaned the ICV, new valve cover gasket w/ NKG plugs, new pre-cat O2 sensors, cleaned MAF a few times. And checked, checked, and checked every hose i can find for a possible leak. But i don't think it would be a vacuum leak since this only happens with the outside temps are 40 F below.
As a side note a mutual friend of mine, who's rebuilt engines for 20 + years, says it sounds like a "weak" MAF as its not calibrating the fuel ratio properly for the colder air. If that were the case I'd surely get some fault codes? My X has 194,000.
I've always used 0w 40 do you think that might be a cause since its actually a bit more thicker than a 5w 30.
Thanks much in advance.
03-08-2015, 01:38 PM
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