Hello, i hope everyone is enjoying the weather. i know i am apart from a problem on my scooby.

The story goes: - once i start my car from when cold the car idles first at just below 1000rpm then jumps up suddenly to 1500 rpm and get to normal idle of around 800 when warm.

When i rev the car on idle to about 4000 prm or have put some load on the engine the idle drops all the way down to nearly zero and it about to cut off unless i blip the throttle then it idles as normal.

Now and again the car idle searches basically idles about 800 normal then goes up to 1000 then down to around 400 then back to steady idle.

I have checked all boost and vacuum pipes - all ok
car boost fine and drives fine
No error codes and checked using plugs.
reset the ecu using plugs under dash.
cleaned the icv valve.

Any suggestion would be very much appreciated. Thank you.

 

Sorry the car is a my99 sti version 6

vf35
fmic
decatt blitz nur
induction kit
ecutek remap

 

coolant temp sensor possibly

 

Fraid I don't have an answer but have pretty much the same problem! Slowing to a halt at a junction sees the rpm drop to 200 or below then hunt for a few seconds and settle at 800. Spec is similar to yours MY99 V6. It did not have the problem before the re-map which was done yesterday so I'm thinking it must be linked it this?

 

Anyone else got any thoughts?

 

Thanks for the replies, tried different things but still the same. Really dont know what to do now. Has anyone got any more advice? Anyone?

 

Possibly a dead maf? I'm thinking that is my problem so will be trying another one later in the week. Cleaning the current one had no effect. They are notoriously unreliable on these year models.

 

hi neutral posistion switch can do funny things, replacement cured my idle issue on my v4 wagon i also have??

 

After being flashed the ECU self learns idle again, just drive it for a few days and it should come good.

 

My v4 sti is like that, cold idle varys between 1000 and about 400rpm when cold for a few mins. Solid and stable at around 800rpm when starting to warm up though.



Not bothered looking into it yet as I plan to get it mapped very soon so will deal with it after that, let me know if you find the cause mate

 

Hi, im going to change the maf and see if that cures anything.

Ive got one spare so when i finish work i'll get onto it.

I will keep you posted.

 

I've had the same problem on V5 type R and got new ECU Apexi and re-map seems to have worked.

 

I have a Subaru Impreza GT MY00 and I have the same problem.

MAF changed --> No joy
APEXi Power FC settings checked --> Nothing found

any other ideas??

 

What's the latest MIAMI? Have you found time to swap your maf yet?

 

+1 its the maf

 

Hi pal, i cant find my maf i had. I left it in the drawer in the back shower room (dont ask). I think my missus must have thrown it as its not there . She doesnt know anything about it.

Im going to have to find another and try it.

 

i had a similar thing and could possibly be spark plugs.(joz)

 

Ah, that's not good news mate....I had to pay the main stealer a visit tonight On the bright side, I got a 5% discount!! On the down side, the new maf was still just over £110 Anyway, it is bought and fitted half an hour ago. Battery is currently disconnected overnight for the ecu re-set so I will report back in due course.

Won't be the plugs as they were changed for iridium ones a couple of weeks ago in the major service

 

Grrrrrr....waste of money!!! Turned out not to be the maf after all Had been getting a strong smell of exhaust fumes from the front end and through the blower so thought I would investigate further. Turns out half of my brand new header to up-pipe gasket has blown out!! Anyway, got the putty out and fired a load into the gap. Put my old maf back on and went for a slow run......huge improvement Idle is stable and only a very slight dip when stopping occassionaly......am a very happy bunny

 

I think you still have some more troubleshooting to do. A leak after the engine will not affect how the car idles.

Would you happen to have a VTA dump valve? Have you tried pressurizing the intake system to check for leaks?

 

The car has a hawkeye sti ic on it and the valve is the oe recirc one which came with it. Have taken it off and checked it. The piston seemed to be free enough. Have had a look for leaks but not pressurized the intake......Will maybe give that a shot...