Engine Vibration

[apaykapuy]

hello and good day to all.

questions and advices please.

1. when the engine is running but it is in stationary(for example - waiting for the stop lights to go green), when i press the brake pedal the rpm will drop and the engine vibrates.

2. when the engine is running but it is in stationary(for example - waiting for the stop lights to go green), when i switch the headlights to "ON" position the rpm will drop and the engines vibrates.

is there something wrong with my yaris?

what to look for?

please help me.

thanks

[MsB]

Problem #1 I think is pretty common and I'm not sure it's anything to worry about too much (though someone may correct me )

The 2nd problem sounds like the alternator maybe on it's way out - the drop you notice is the electrical power draw/demand possibly not being coped with, if it is that eventually it won't recharge the Battery. Best thing would be to find a friendly mechanic/garage or even a parts shop that know what they are doing and get it checked

[Chris81]

Both normal I'd say. They're both down to electrical load being drawn from the engine and I've noticed it on my Yaris occasionally, revs drop as if the engine is about to cut out but then it stabilises. Same happens when you turn air con on. The Yaris revs very low at idle which doesn't help.