hunting and ticking over at 1100-1300 rpm
 

Ive recently changed my lambda sensor as advised by my ecu code on my 97 sti yet still I have this problem. I think I hear an air leak when driving but cant find it when not moving. Doin my head in now.

Have you looked at your maff sensor?
I had this last week,hunting between 500rpm and 1000.The engine light didn't come on so there was no code.
There was a thread on here about the same thing and I was told to change the maf.Problem was sorted.

Did you reset the ecu after changing the lambda sensor?
Another symptom mine had was a slight hesitant feeling when I was driving along under 2000rpm.Does your's do this?

Danny.

Hi danny ye I clean the maf as the hoses were pretty dirty from using hks shroom filter. I did an ecu reset but check light would signal its complete. seconds after driving part of reset. Mines fine when drivin at low rpm but im unsure if theres a leak or if its my vf32 spooling

Hopefully someone can advise on where to start looking for an air leak.
It could be worth cleaning the idle control valve as well.There's a thread on here somewhere that I saw the other day.I just can't seem to find it.
I don't have much luck with the search function.

Danny.

i would inspect the exhaust system. If there is a leak close to the lambda then it could be false reading

the exhaust system was only put on a month ago with new gaskets. im soaking the ICV atm.

Ive now clean the icv, but once closed it doesnt retract as it should. Ive just put another maf on it. As my icv is wound down as far as it goes and stil revs at 1300rpm. Would I wind the icv to the centre then do ecu reset or leave it where it is??? New icv on order.

No change on the revs with the new maf. I did a ecu reset but the light flashed as soon as I drove. Help

When you performed the ecu reset what exactly did you do?
Did you use the wires under the dash to reset and run the onboard diagnostics?
If you did then the flashing light should give you a code.

Danny.

Il giv it another go later but im pretty sure it flashed every 1-2 seconds, meaning its fine

there was no error code...
im confused

See someone that knows, I dare say the right person (not just any subaru garage) could get to the bottom of it in half an hour.

You won't get an error code because the ECU doesn't see anything obviously wrong, and it certainly can't know about an air leak for instance unless it causes an out of range reading one one of the sensors (unlikely).

Things you need to do:

Take the top of the ISCV, make sure the spindle rotates side to side completely freely, if it doesn't work it in each direction until it frees up.

Check the voltage on the throttle position sensor, it should be 0.7v when the throttle is closed, if it's far enough out the ECU will not think the throttle is closed and won't go into idle mode.

Check for air leaks, vacuum hoses in particular.

Have you replaced the MAF sensor? If not then I would do that forthwith.

You've changed the sensor but have you checked the wiring for the sensor?