Need help to see if i've got a problem with my mk6 fiesta. the car bucks when i'm stuck in traffic that's crawling along. It does it in first and second gears when the rpm drops just below 1000. my old car used to just crawl along in first and second with no problems.

really appreciate any help.

The engine is trying to stall matt. Did you have a diesel before?

Your letting the revs drop too low. The engine idols at that speed.

Agreed Willy ma mk6.5 used to idle at 800 to 1k but wouldn't like under 1k but best to keep between 1k and 1.4k for gear changes to move forward in gear as Willy said it idles at that

Check the vacuum hose between the PCV valve and the inlet manifold, if it is split or has deteriorated at the ends it will draw in air and cause this problem. Its worth checking the PCV valve too, if it rattles its usually a good sign that its working.

At engine idle the vacuum in the manifold is higher so will try and suck air in from anywhere that it can.

thanks for the help. will check out the vacuum hose you suggested. I'm a bit clueless when it comes to cars. before i had a 1.0 litre corsa (petrol)

It's the way the car is geared if you leave the car in second I don't let the revs drop below 1k if im in slow traffic and the road sort of allows your best bet is to just dip the clutch and then by the time the traffic moves again you will be able to select 1st and start again, it's just longer gearing than the corsa had.