sitting at 1500rpm

[Andyman]

My mk1 172's decided it wants to idle at 1500 rpm. Sometimes it'll pick up to 2 as well.

From cold it idle's perfectly how it should.

Ive cleaned the throttle body out and that seems fine.

One strange thing when im stationary is when its reving up, if i let the clutch out to the point of just about stalling [not touching the accelerator at all] at just about 1000rpm and lift off the clutch totally, it goes back to idling normally !!

Any idea's what the problem could be ??

Thanx

 

[Andyman]

bump

Also, when the cold air feed pipe is connected to the Viper it revs up and down between 1500 and 2100rpm !!!

Air flow meter do you think ??

 

[Jones]

Cant be the air flow meter as they dont have one they have a Manifold Air Presure sensor (MAP). Does it idle normally with the standard airbox on?

 

[Andyman]

Cant be the air flow meter as they dont have one they have a Manifold Air Presure sensor (MAP). Does it idle normally with the standard airbox on?

I havent tried it with the standard air box on tbh.

On cold start its perfect, its just when the thing gets warmed up it all happens.

I cleaned out the idle control valve and the throttle body is cleaned up too. Also i havent got a gasket prob cos the engine cuts out when i hold my hand over the viper so it dosent appear to be blowing.

 

[Andyman]

Anyone else have a idea what this could be ?? :]