bj

Hi All

My cruise control from time to time adjusts itself by speeding up abruptly in order for it to correct itself. Any thoughts as to why this is occurring.
BTW - Adrian's suggestion as to the cruise intermittenly not working was in fact due to the micro switch on the clutch as he suggested - Thanks Adrian. When it doesn't work I simply pull up on the clutch and this fixes it. Could this switch also be causing the sympton above?

Thank you in advance
Bill
90C2

Adrian

Dear Bill,
I would certainly recommend you replace this microswitch. It only interrupts the cruise control circuit whereas the brake microswitch disconnects the cruise control.
After this I would check the vacuum lines connected to the cruise control unit on the top of the engine. It is almost in front of idle speed control valve (idle stabiliser). Silver thing at the back of the engine bay on top of the throttle body housing assembly.
Control linkages might also be sticky. This was the subject of a voluntary recall notice for your 964.
Ciao,
Adrian
911C4

Here is some data on fixing up your clutch switch.
Models Affected: 911 Carrera 214

Concern: A loose or misadjusted clutch pedal switch may cause the cruise control to become inoperative.

Repair Information: The clutch pedal microswitch should open with clutch pedal depressed 15 + 2 mm (audible click). If necessary, loosen switch mounting screws and adjust switch. Make sure mounting screws are tight after adjusting or when checking switch.