Help? Annoying

[mattih5]

Hi,

I purchased a 172 a few month back and this has happened a couple of times now. When I start the car, sometimes it is fine and sits at between 800 and 1000 revs in idle mode. But other times it will start and fluctuate quite a lot until I rev it and it begins to settle to the normal level. Other times it will start but the revs will completely drop until the engine cuts out. And this morning it took quite a while for the care to actually start. By this I mean the car ticked and ticked and then started.

I'm not sure what it could be, anyone help?

Thanks,

 

[edde]

Check the TDC sensor.

 

[mattih5]

Hi, my mechanical knowledge is very short, how do i get access to this? Is it just a matter of cleaning it? What does it actually do?