not stable rpm

[jun]

stopped at the traffic light using gear D..the rpm is not stable...n car shaking
is it becoz of my air flow sensor busted?

[Denlasoul]

Hello and welcome.

Your problem has come up many times in previos Threads, I suggest using the Search button and type "RPM" and select the Repairs section.

[jevous]

Yeah... I get that as well..the rpm is not stable, it hovers about 700 rpm but the needle moves up and down (1mm). I'm not sure if I should be alarmed about this but there are times (once or twice) the car kind of jerks when i come to a stop. So, i'm not exactly sure where to begin with. I know i've got to replace my engine mounts and possibly, gearbox mounts but i'll start with the engine mounts sometime this week. Although it's nothing to do with the non-stable rpm, i think my engine mount is due for replacement coz apparently, it has cracked and is out of place ? At least, that's what the mechanic tells me. But because i don't notice a "significant" vibration while stationary or moving, i didn't bother about changing it during my last service.

I did a search like you recommended but they seem to point towards a faulty MAF sensor ? I'm not entirely sure what that does though.

Another issue i have is sometimes, when i shift to "R" , it gets a "lock-up" before i can actually shift it properly. Only sometimes. This happens mostly when i've just started the car and shift it into "R" and i do notice a slight hissing sound when i shift to "R". Has that got anything to do with a leaked vacuum ? Any way to check this myself ?

Cheers