PT Cruiser Earthquaking

I have 2006 PT Cruiser Turbo Convertible that violently shakes when I am stopped at idle in gear and the A?C compressor is on. When I turn the A/C compressor off (leaving the fan on) there is a drastic reduction in the vibration. If I put it in park and turn the fan off, there is an additional lessening of the vibration.

I have taken it to three different mechanics and had the following done: spark plugs and spark plug wires changed, fuel injection system cleaned, the ‘whatchamacallit’ in the fuel system cleaned out, the two main motor mounts changed.

None of the above maintenance has lessened the vibration one bit. Question: What is causing it?

My first suspect would be the Idle Air Control valve. It can usually be cleaned with some carb cleaner.
A second suspect would be a vacuum leak of sorts. Spray a small amount of starting fluid around rubber hoses while the car is idling. If the idle suddenly changes as you spray, you’re warm to where the leak may be.

It is hard to believe a mechanic wouldn’t try that first, tho…

Have you checked the PTCruiser forum? You may have a bad radiator cooling fan. Apparently this is a common problem, that the fan draws too much current and causes the engine to run rough:

Nice find! I would have never suspected a radiator fan.

I would never have guessed a fan either, but The Google knows all. :wink:

Yeah, what /did/ we do before this interweb gadget??
I perused that forum. Interesting. Don’t know anyone with a PT cruiser but that’s a good thing to remember.

Thanks guys! I will try all your suggestions