I appear to have the much talked about idle dropping and engine stalling problem. When the engine is warmed up e.g( been driving for 30mins on a dual carriageway) and i stop at a junction,the revs fall below the usual 800rpm point and either pick up again or stall . Ive tried starting the car without the air mass plugged in and it wont start, so does that mean the air mass is fine? Ive also cleaned the air mass and the idle control valve. I even changed my vta dump valve to a re-circ because i thought that might be leaking. Please help, i've just had a rebuild and dont really fancy another one

 

see if you can lend a maf from someone
check plugs gap/coil packs/lamba etc etc

 

Usually MAF, but you tested and it stalled so may be OK.
ICSV if dirty or top has moved

Air leak after MAF ...

Std ECU? If not are idle settings set right for hot & cold driving?

else as above, plugs, coil packs etc.


I get same problem if I replace my recirc dump valve ( a forge one ) with a vta one, or blank off air return at inlet and leave recirc to atmos! After a mile or so starts to rough idle then stalls at junctions and traffic lights!

 

Usually MAF, but you tested and it stalled so may be OK................... dont take this for granted as this is not always the case

 

How much are MAF's? Am i right in thinking about £250?

 

What year is your car? My Maf for a UK MY99 was approx £90, remember you only need the cartridge not the whole assembly. Earlier cars are a little more expensive.

 

its a 98sti, orange label maf

 

I have the same problem on my04 wrx. its been to 2 different dealers on many occasions and they can't find a problem. Very frustrating.

 

Frustrating, annoying and embarrassing! Ive just changed the lambda now so lets see if that makes any difference

 

I agree, very embarrassing.

Just tryied running it and disconnecting MAF, it cut out. does this mean its using the MAF signal and not an ECU substitute value and its ok?

 

Idle problem? Just clean or change the IDLE AIR CONTROL VALVE. The clue is in the name of the component.