Rpm gauge moves up/down while in park/neutral mode

[funky05]

Just wanna check, my car rpm is default starts at 1 instead of 0 needle when I start the engine.. Last night I realized when I put the gear to neutral, the rpm moves up from 1 to 1.3 and moves down back to 1 and continues doing so for about 6 mins without me pressing on the accelerator.. Is there anything wrong? This is my first time encountering this.. Ride is wira 1.3M

 

[RuOnline]

Just wanna check, my car rpm is default starts at 1 instead of 0 needle when I start the engine.. Last night I realized when I put the gear to neutral, the rpm moves up from 1 to 1.3 and moves down back to 1 and continues doing so for about 6 mins without me pressing on the accelerator.. Is there anything wrong? This is my first time encountering this.. Ride is wira 1.3M

Maybe throttle body dirty that cases the unstable revving. Can go ws have a check.

 

[ZhuTou!]

Maybe throttle body dirty

 

[funky05]

Thanks for the replies.. Based on ur experience, Issit a major issue which requires urgent attention?

 

[ZhuTou!]

Thanks for the replies.. Based on ur experience, Issit a major issue which requires urgent attention?

its good to solve it earlier
if not car may died off while idling
quite troublesome coz u need to start engine again

 

[k3vvie]

Air con on or off? Might be the air con compressor kicks in. Den thr rpm goes lower n the ecu revs up the engine so that it won't stall?

 

[pew]

If its the throttle body, make sure the mechanic take out the throttle body and clean. Not spray the throttle body.

 

[meganut]

another possbility could be your idiling sensor dirty or a broken wire in sensor...

 

[St00ky]

my dad's car RPM gauge also keep moving up and down and there is also some vibration whenever i step on the brakes. no issues when putting the gear in neutral and park. is there a problem with the idle air control valve?

 

[ZhuTou!]

Rpm maybe throttle body
Step brake vibrate maybe rotor

 

[pro326]

Does this happen when the engine is cold? See below

1) In the morning
2) after your car is parked for a few hours

Confirmation:
When you drive, your car will die. After a few times your engine check lights comes on??

If the erratic idling cease after the car is warmed up, then there can be a possibility that your throttle body sensor is faulty.

This just happened to me. The repair depends on your car.

 

[Marbok_Tan]

Just want to check whether it is normal for a Merc B class to experience shaking when idling? while stopping at a traffic light i notice sometimes the RPM needle will dip slightly followed by rough shaking. I didn't get any check engine light or any error messages. Just wondering if it's normal. My family's previous cars dun have this kind of problem

 

[Geylang Prawn Seller]

Which b class year? Chassis code w245 or w246?

 

[Marbok_Tan]

Which b class year? Chassis code w245 or w246?

2008 w245. just read from another forum that its normal for the B class to shake during idle

 

[Geylang Prawn Seller]

Yeah it's normal. Engine mounts tend to crack at the 7 year mark. But despite new engine mounts these cars tend to vibrate. Don't worry about the rpm it's just the cvt doing it's stuff