revs @ idle

[cruisermaine]

I noticed something while driving to the dealer for the new manifold this morning. Typically, the idle speed is a steady ±600rpm. Occassionaly however, the revs will suddelnly rise to 800 for a a minute or so then they drop back down. When this happens, I can just make out the sound of a relay or solenoid at the start /finish of the cycle. Is this normal? Does anyone know what triggers this change in revs? I did not have the AC on at the time.

 

[NMuzj100]

Maybe this is the electric brake booster pressurizing the master cylinder ?

 

[ShottsUZJ100]

Maybe this is the electric brake booster pressurizing the master cylinder ?

AC compressor kicking in and out? You'll hear the click as it kicks in and out too.

 

[cruisermaine]

Maybe this is the electric brake booster pressurizing the master cylinder ?

this was /is my guess....

AC compressor kicking in and out? You'll hear the click as it kicks in and out too.

As I said, I did not have the AC on.

Has anyone else noticed this?