vibration and craking noise in the morning

It can be. Unburned hydrocarbons in the manifold can wreak pre combustion havoc.

Never power down with the engine running

 

okay

 

What???

 

if you stop the warm up process, unburned hydrocarbons can collect in the intake manifold and cause detonation on the next start.

 

I have never heard of this being an issue on any engine other than a rotary. And that’s only because the gas pooled at the bottom of the rotor chamber and washed away the oil from the apex seals. On an Atkinson cycle engine some of the fuel/air mixture is always pushed back into the intake manifold. I guess when the engine is cold there is a higher amount of fuel in the mixture like a choke on a carburetor. Is that what you are talking about?

 

i don't know what i'm talking about. just what i have read in the 'crash, bang, boom when i started my car' threads, and toyota's 'improved' intake manifold tsb which didn't work.

many of those said they had moved the car in their yard the last time they started it and shut it down while the engine was running.