as above when the car is started it idles fine till you touch the throttle and back off the revs drop to 2-300 rpm need to keep it on throttle to stop it stalling it only does it when cold till its warmed up then it seems ok,just had exhaust replaced and the mechanic said its running rich but there are no faults on the ecu or lights on the dash,help!!!!

 

You checked the condition of you're plugs?

 

had full service 3k ago and oil change 1k ago at the stealers but ordered new plugs to be safe,cos its an import they arent really interested in fixing it more interested in selling me a new one

 

possibly one of your coil packs

 

Do 99 spec cars have individual coil packs,im sure its only the single one on top of the inlet manifold,would knacked plugs and leads not make it run crap all the time it seems better when warmed up but did notice it dont pull the same as it used to,pretty sure if i rr'd it would be down on power

 

yeah, new plugs and smooth running when hot would suggest it's sparking ok.

Sounds like you need to find out why it's running rich, - post maf leaks or a dodgy idle control valve might explain why it can't hold load at idle.

 

Could be your idle control valve?

 

this could be a number of things really. spark plugs not fitted properly or old. as the car warms up the sparks can jump alot more so if sparks or coil packs are warn then when cold will be bad and nearly cut out but when hot electricity can jump better.
it could also be heat sensors, there are louds on the subaru so best to check ones you might have been near. like if you have fitted an exhasut then theres an o2 sensor in the standard exhaust downpipe.

all imports run rich as they are set to 100 octane fuel as standard. my import runs around 7.9 lambard on an MOT. go tescos they do 99 octane fuel

 

what the chuffs a heat sensor?

 

heat sensor?I bought a downpipe from an ra with a wierd sensor my car didnt have,thought it was the o2 sensor turns out it wasnt so needed another one i guess tht must have been a heat sensor.Ill get the plugs changed,maf was done a few weeks ago,and try a new o2 sensor see if that makes any difference,if not then ill look at the idle control valve