I thought I'd try and bonk some knowledgable heads together,

 

Have a problem with an MR2 turbo, stock apart from exhaust and blitz induction kit. If idle is set to standard of 750 RPM the car appears to run fine but every now and then it will stall whilst idling, usually when light on the accellerator or just coming off, If the idle is adjusted to 1200rpm the car will not stall but every now and then the revs will drop to around 400rpm. Obviously the high idle is stopping the car from stalling.

 

What could be causing this? I've replaced the AFM (air flow meter) as this is what garage reported the problem as being, however the problem persists.

 

Apart from that one problem the car runs fine, when its running it is quick and boosts correctly.

 

any idea guys, or is it looking like something serious?

could be almost anything - do they have diagnostics? worth checking if theres any fault codes.

 

other than that id check for air leaks (any split vacuum hoses etc) & clean the TB. does it have an idle valve? also worth a clean if it does

ta paul, would the vacuum leaks cause boost to not fully be reached? it has an aftermarket boost gauge and is boosting to .7psi when warm and 0.5 when it goes into mr2 "safety" boost.

its possible mike, depends on the severety of the leak - it may be just enough to draw in excess air & lean out on idle causing problems.

Mike - I believe there is an ECU diagnostic you can do, similar to ours, but involves inserting an unfolded paper clip into 2 pins in the ECU connector.

 

A look around http://www.imoc.co.uk or http://www.mr2dc.com should give the exact method.

 

Pete

Is your car a Rev 3? If so the it could not be the airflow meter as the Rev 3 models had a map sensor instead.

 

Justin

its a revision2,

 

Nothing comes up on diag, I thought replacing thermostat and AFM would correct the problem, it nows runs fine and heats up ok but it will randomly stall unless idle is turned up!

 

AFM looks looks like an extremly crude way of measuring airflow....