986 Forum - The Community for Porsche Boxster & Cayman Owners - View Single Post - Running the heater makes the whole car shake

thstone · 12-15-2011, 01:14 PM

My guess is that the problem is in the idle control - its not properly adjusting for the added load of the A/C.

When you turn the fan on in Auto mode, the A/C compressor comes on and extra load is bogging down the engine idle to where the car shakes. Turn off the fan (and thus the A/C) and the idle resumes to normal in a few seconds.

12-15-2011, 01:14 PM	#8
thstone Certified Boxster Addict Join Date: Nov 2010 Location: Los Angeles Posts: 7,669	My guess is that the problem is in the idle control - its not properly adjusting for the added load of the A/C. When you turn the fan on in Auto mode, the A/C compressor comes on and extra load is bogging down the engine idle to where the car shakes. Turn off the fan (and thus the A/C) and the idle resumes to normal in a few seconds. __________________ 1999 996 C2 - sold - bought back - sold for more 1997 Spec Boxster BSR #254 1979 911 SC POC Licensed DE/TT Instructor