My F is showing some rather odd behaviour of late in terms of low revs at idle when stationary and worse when I'm actually driving her. During normal driving, she appears fine. When I'm shifting down and approaching a stop, clutching down into 1st seems to result in revs dipping down to almost zero on most occasions and often results in a complete stall. Same thing when reversing at really low revs - take my foot off the clutch to select 1st to move away and she drops to almost zero and again will occasionally stall.
As you can see from the video (which was shot whilst stationary) the revs drop down fine when revved hard, but when a gentle blip on the throttle is pressed, the revs go right down and it almost stalls most of the time.
Does anyone have an idea what is causing this behaviour and what I can (or should) look at first to try and remedy it?
Here's the short video - about a minute in length:
Oh, I should add that I've already done the TPS reset procedure several times when the engine was up to temp - no difference. Actually, when the car is just sat idling with no throttle action at all, she quite happily sits at 750-800rpm with no hunting up or down which leads me to think that the throttle (52mm which I upgraded recently) is maybe not the cause. I'm a bit stumped as I'm no mechanic, really. I could do with some help to try and sort it out.
Thanks in advance of your replies.