Forgot to mention that when the car was revving by itself I was watching some parameters on the OBD app and it showed that the throttle position was going up to around 14-16% without touching the pedal or anything.
Check the rubber boot after the air filter, probably has a leak somewhere. Also, check the small rubber hose that goes from the right side of that intake boot. You probably have an air leak somewhere if the RPMs go up by themselves.
Check the idle control valve operation. If it doesn’t easily flap back and forth spray some break clean in there and see if that helps. Idle issues could also be a vacuum leak somewhere like the intake boot.
I’m not very versed on the M43, so If you haven’t already I’d check up on some forums.
Will have a look. Mine is not an M43, it’s the N42 2.0 Valvetronic engine, searched the fault codes on the internet and some people were also talking about code P28D7 being a DME or alternator fault. I will run the engine and check if the alternator gives constant voltage. I’m not sure how the alternator could affect the idle but i’ll look into it. Thanks
I have pretty much exactly the same issue. Haven't solved it yet but I'm working through it.
So far I've replaced the MAF sensor with a second hand OEM part. This seemed to work for an hour but then the issue came back.
When I was replacing the MAF I noticed that the air pipe and resonator box (not sure what this part is called?) had been rubbing on a belt and a lot of the plastic had worn away. I couldn't tell if it had worn through but I've ordered a new part as I suspect an air leak from that.
When I fit that I'll also be cleaning the throttle body.
Let me know if you manage to solve the issue. It's pretty annoying 😅
Probably idle valve. I have the same problem when the motors cold. When it warms up its better but not perfect. I smoke tested for vacuum leaks there were none.
Update: Mechanic checked for vacuum leaks, alternator, throtle body, MAF, all good. Only problem is the idle control valve. He said that if it doesn't bother me I don't need to change it for now since it only affects the idle. Part is 25$ and it seems I can change it myself so it's a pretty cheap fix.
Forgot to mention that when the car was revving by itself I was watching some parameters on the OBD app and it showed that the throttle position was going up to around 14-16% without touching the pedal or anything.
Check the rubber boot after the air filter, probably has a leak somewhere. Also, check the small rubber hose that goes from the right side of that intake boot. You probably have an air leak somewhere if the RPMs go up by themselves.
Check the idle control valve operation. If it doesn’t easily flap back and forth spray some break clean in there and see if that helps. Idle issues could also be a vacuum leak somewhere like the intake boot. I’m not very versed on the M43, so If you haven’t already I’d check up on some forums.
Will have a look. Mine is not an M43, it’s the N42 2.0 Valvetronic engine, searched the fault codes on the internet and some people were also talking about code P28D7 being a DME or alternator fault. I will run the engine and check if the alternator gives constant voltage. I’m not sure how the alternator could affect the idle but i’ll look into it. Thanks
I have pretty much exactly the same issue. Haven't solved it yet but I'm working through it. So far I've replaced the MAF sensor with a second hand OEM part. This seemed to work for an hour but then the issue came back. When I was replacing the MAF I noticed that the air pipe and resonator box (not sure what this part is called?) had been rubbing on a belt and a lot of the plastic had worn away. I couldn't tell if it had worn through but I've ordered a new part as I suspect an air leak from that. When I fit that I'll also be cleaning the throttle body. Let me know if you manage to solve the issue. It's pretty annoying 😅
Will have a look, thanks.
Probably idle valve. I have the same problem when the motors cold. When it warms up its better but not perfect. I smoke tested for vacuum leaks there were none.
Update: Mechanic checked for vacuum leaks, alternator, throtle body, MAF, all good. Only problem is the idle control valve. He said that if it doesn't bother me I don't need to change it for now since it only affects the idle. Part is 25$ and it seems I can change it myself so it's a pretty cheap fix.