Hey peeps.
05 wrx wagon full decat and reconditioned gearbox.
Think the issue only started after recon gearbox.
The revs sometimes drop when coming to a stop at lights etc.
Doesn't stall and doesn't do it all the time.
1 in every 5 slow downs.
Cheers. Justin

 

MAF sensor?

 

Agree with MAF as I had the same symptoms but was thinking about the Neutral Position Switch as this is on the gearbox.I don't know if the NPS will cause the same symptoms.

Anyone with more knowledge enlighten us?

 

Maf or iac but think the iac puts the cel light on so leaning towards the maf

 

Mine does it when I first start it? As soon as I take it out it stops. Getting remapped shortly so hopefully it will get sorted. Named my car Damien as it only does it with me never does it when missis starts it.

 

Hmmm.
I just don't want to throw money at a maf if it's not it.
At the moment it's not a problem as it's not that bad.
I might put the Bluetooth obd reader in and see if anything shows.
When I bought the gearbox the guy was selling a sensor with the box as well which I didn't buy but I can't remember what sensor it was.
Nps or some speed sensor.?

 

I think it's gearbox related as I had the car remapped and the gearbox broke on the way home.
I'm pretty sure it didn't do it before gearbox change.
Could it be a dirty contact somewhere sensor related.

 

Finally think I cracked it today.
I cleaned the iacv and replaced the intercooler gasket. This didn't cure it.
So I then gently tried to clean the maf.
Still no good.
Went back inside defeated.
More Internet searching and found a thread on throttle body cleaning.
So went back out, took intercooler off and cleaned the metal disc with brake cleaner and a rag,I also noticed the pipe between intercooler and throttle body was oily on the inside and maybe wasn't sealing 100% so I cleaned this all up as well.
Tightened it all up thoroughly and hallelujah 🙌 it's stopped doing it.
I've also noticed that the idle seems more stable when stationary.