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HI! i,m new to this,so be nice,i recently changed cam belt on 2003 impreza single cam [ej201?] ,runs good until warmed up then starts to miss intermittently and dies ,did basic service,plugs,oil/air filter ,did not touch electronics ,compressions are good,check engine light does not come on but am getting fault codes 13,31,33,23,24,should i buy a cheap scanner OR BURN THE IMPREZA AND KEEP THE BRUMBY,THANKS!

23 Air flow sensor Abnormal voltage input entered from air flow sensor Controls the amount of fuel (injected) in relation to engine speed and throttle sensor position X X
24 Air control valve Air control valve inoperative (Abnormal signal produced in monitor circuit) Prevents abnormal engine speed using "fuel cut" in relation to engine speed, vehicle speed, and throttle sensor position X X
31 Throttle sensor Abnormal voltage input entered from throttle sensor Sets throttle sensor's voltage output to a fixed value X X
32 Oxygen sensor Oxygen sensor inoperative none X X
33 Vehicle speed sensor Abnormal voltage input entered from vehicle speed sensor Sets vehicle speed signal to a fixed value X X

Try resetting the ECU and see if the codes return. See here : Fault codes and resetting ECU

If it starts and runs OK when its cold it is not anything major

THANKS for the information,like the brumby[how about 4LT. v6]

hmmm...what grade oil does the Imp require for your environment, and what grade did you feed it? Thicker grade can cause lifter pump, holds valves open, stalls, starts better when oil bleeds down out of over stiffened lifter - Hydraulic valve lash adjuster really

If this has only happened since you changed the cam belt, check it.
The positioning can vary once you release the tensioner.
Did you turn it over 360 deg, then check the timing marks?
Keep the Brumby, no need to burn the impreza, but keep the Brumby.

THANKS GENTS for info& suggestions, i tried a few things,now it runs OK for about 5K's then power goes on/off and eventually stops, let it cool down and it runs again,no check engine light showing, won't rev over 4k.could injector cleaner have caused some damage?

cordeck wrote:could injector cleaner have caused some damage?

No it just cleans the injectors.

Still suspicious bout what work you've done on it...timing belts, what else?

If the car ran fine until you changed the cam belt, it must be something that was altered/unplugged during that process. It would be a huge coincidence (although not impossible) if another part just happened to fail at the same time. Can you think of anything that you may have disconnected or re-arranged during the cam belt job?

Check the timming marks..the crank pulley can catch people out with its marks.if you lined up the arrow on the front of the pulley with the timming mark then that's your problem...the real mark is at the back on one of the fingers..there the crank angle pick ups.

Sounds like either a crank angle sensor or cam angle sensor failing when hot.
When it does it again, try pouring cold water over them to see if it makes a difference.

THANKS AGAIN GENT'S don't think its cam timing or a mechanical problem because it runs fine for about 8 K's

Still sounds like cam/crank angle sensors, or blocked fuel filter/lazy fuel pump.

If it was something to do with the timing belt, it would be missing from start up wouldn't it, not a few ks down the road (when warm)?

"If it was something to do with the timing belt, it would be missing from start up wouldn't it, not a few ks down the road (when warm)?"

Correct.