Technical Low-high revs?

[TempraTDSX]

Hi All, I searched but couldn't find anything related to this, so apologies if it's detailed in depth somewhere!

My Cinq on start up revs high low high low high low high low repeatedly even after it warms up? No idea what it may be? Any help much appreciated

 

[TheShadows645]

Hi All, I searched but couldn't find anything related to this, so apologies if it's detailed in depth somewhere!

My Cinq on start up revs high low high low high low high low repeatedly even after it warms up? No idea what it may be? Any help much appreciated

I would guess idle control valve but see if woj or dave is about because I imagine theyd be able to know for sure

 

[Ouby]

Could be one of many problems:
http://www.autoserviceprofessional.com/article/92420/the-dreaded-engine-surge#
A sticking Idle control valve is fairly common on the Cinq/Sei but the first thing i would check for would be an induction leak, extra air can be getting into the system through a split on one the hoses going to the Throttle Body or possibly a gasket leak where it mounts on the inlet manifold - won't cost you anything but time to check this.

 

[fingers99]

Hunting idle (up and down) is likely a sticking idle air control (whip off the TB, clean outside, then inside, with carb cleaner). High idle is usually air leak on vacuum side (that is, between throttle butterfly and cylinder head) or sticky throttle cable.