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Discussion Starter · #1 ·
Hi guys, I have had my 05 RS for probably 3.5 years now and its been great have not had a single problem with it until a few months ago.

What the issue is when I'm out driving and I either engage the clutch or shift the car into neutral the engine revs up by itself. It revs up to around 3-5k by itself. Sometimes the rpms will stay up there, or sometimes they'll climb, stay there for a few seconds and drop back down.

I've had the car at the dealership for about a month now and they are really having trouble figuring it out. They even brought someone in from outta state to look at it. So far they have replaced:

1. Fuel Injectors
2. Flashed the ECU
3. Some type of clutch switch or some type of sensor
4. And I think something with the gas pedal
5. Throttle body

Ive scoured the internet trying to out if anyone has had this issue and havent had much luck besides one person. They had the same yr and model of my car and the same exact problem. For him it ended up being the rear o2 sensor. So i let the dealership know about that.

If anyone of you guys have any ideas I would appreciate them incredibly much. They have had my car for over a month now and its getting very frustrating! Im losing out on alot of money from missing some work. The dealership has been great though they have been really cool with the whole thing, they havnt charged me anything but $40 so far for flasing the ecu.

Thanks for reading guys, if you have any ideas or suggestions I would GREATLY APPRECIATE them. Thanks again guys.
 

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05 STi WannaBE
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Try cleaning out the MAF sensor with the appropriate cleaner and do a hard ECU reset. I would also clean out BOTH O2 sensors with the same cleaner (trust me it works). If you dont know how to do a hard ECU reset let me know.
 

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05 STi WannaBE
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Do this:

*Turn on your dome light (important step to drain all electricity from the ecu)
*Disconnect your battery
*Make sure you have a clean air filter
*Unscrew your MAF sensor and clean it with this > CRC/Mass air flow sensor cleaner
*Unscrew BOTH 02 sensors and clean them with the same stuff
*Put everything back together and reconnect the battery
*Start the car after the DBW throttle stops clicking
*Let the car idle completely until warmed up then shut the car off and let completely cool down

The last step is very important because our throttle bodies are DBW (drive by wire) and its all controlled by electronics. The idle warm up procedure lets the ECU learn where exactly the engines idle is set.
 

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Discussion Starter · #8 ·
Thanks for all the replies guys, i really do appreciate it. I dont have the car in my possession its back up at the dealership.

Im kind of losing faith in the dealership. The dealership gave me back the car twice as being "fixed" and before I even get home the car is still having the same issue. I can understand this issue is hard to diagnosis but really? Do they even test drive it more than a few minutes?

On monday Im gonna call them and recommend some of these things for them to try. I really dont know what to do if they cant figure out the problem.

When they run a diagnosis scan nothing comes up. Is there a possibility that something could be wrong with one of the sensors or something and it not come up on the scan?
 

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Red 2007 BMW Z4 M-Coupe
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Sounds life you may have something stuck in your throttle body that keeps it open slightly. Also find a wideband and check your air fuel ratio if nothing else works. This would tell you if your engine is burning all the fuel or not. Could be useful for further troubleshooting.
 

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Discussion Starter · #11 ·
Do these procedures by yourself at our home to cut out on the downtime. There super easy to do BTW ;)
Ya I might do that, I'm good with working with tools and that type of stuff but I dont have much experience with cars. Ill give it a try, thanks

Sounds life you may have something stuck in your throttle body that keeps it open slightly. Also find a wideband and check your air fuel ratio if nothing else works. This would tell you if your engine is burning all the fuel or not. Could be useful for further troubleshooting.
The dealership replaced the throttle body and had no effect.

Ya it boggles my mind.
 

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Discussion Starter · #12 ·
Do this:

*Turn on your dome light (important step to drain all electricity from the ecu)
*Disconnect your battery
*Make sure you have a clean air filter
*Unscrew your MAF sensor and clean it with this > CRC/Mass air flow sensor cleaner
*Unscrew BOTH 02 sensors and clean them with the same stuff
*Put everything back together and reconnect the battery
*Start the car after the DBW throttle stops clicking
*Let the car idle completely until warmed up then shut the car off and let completely cool down

The last step is very important because our throttle bodies are DBW (drive by wire) and its all controlled by electronics. The idle warm up procedure lets the ECU learn where exactly the engines idle is set.
Do you know of any reference material I can refer to find out where the MAF and o2 sensors are? Thanks
 

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05 STi WannaBE
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Your catalytic converter should look just like this but with the heat shields still attached:



Your MAF sensor is located right after your air filter. Be carefull not to loose the 2 tiny screws:

 

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Discussion Starter · #15 ·
do you have your cruise control on when it happens? gotta be something with the drive-by-wire system
No, no cruise control on when im having issues. Thanks for the reply.

thegoldenfist- thanks a bunch buddy, I really appreciate that! When it comes to that type of stuff with cars I have no idea what im looking at. Thanks a lot bro
 

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2001 RS2.5
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Oddly my wife's '96 Legacy was having a similar issue. I cleaned throttle body which helped some. A mechanic suggested the coolant temperature sensor, which I replaced....this did the trick. However, the car was not revving on its own....when I put it in neutral it would maintain RPM's and slowly die down. It's a cheap and easy potential solution. Hope this helps.
 
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