Hi... And Some Focus Trouble Shooting Help... Please!

Hi, I've just joined, this looks like the place I need... hopefully.

Bit of background..

I've always had Fords.

My current car is a mk1 focus, 1.8 zetec 4 dr hatch x reg - 2001 collection model)

we first met 4 years ago, she had 68000 on the clock, full service history with a major service every year or 10,000 at the local Ford dealership.

we have had very few drama's together, I got the rear doors re-sealed under warranty a couple of years ago, after a little battle with Ford.

Apart from that, a wishbone, anti roll bar link, mid and back exhaust, a battery and had to re-program the key. So in my mind, reasonably trouble free motoring.

she's now on 116000, a few moths ago she started idling far too high, or far too low with no pattern whatsoever, this gradually got worse to the point where sitting in traffic she would rev upwards of 3000RPM or below 200 - and stall.

As this became a big problem I investigated, and found the pipe from the PCV valve to the inlet manifold was spongy on the bend and sucking itself shut (quite a common problem I believe).

Got a new one from Ford, fitted and reset the ECU.

Went for a drive and all was great.

...until the next morning, when the rough idle came back but much worse, really shakey and stalling all the time!!

I then reset the ECU again and took her on a road trip, some fast driving, slow driving, town driving and motorway driving.

Since then the idle has been perfect, drops slowly and sits around 800, give or take 50rpm approx.

However.. shes now running a little 'lumpy' on acceleration and if I coast she judders a bit, also if I put the air con on, the revs don't pick up, the dash dims and stays dim, the revs idle lower (before the ECU reset the air con would kick in and give the revs a boost of around 100rpm).

Is it possible I have caused more harm than good with the ECU reset, its been 200 miles now since the reset and i cant see it sorting itself out.

So far all I have done is have a look inside the throttle body, there's quite a build up of black stuff in there, not sure if this can be cleaned as it says not to on it?

I did remove the plug from the MAF which made the problem alot worse.

The only other thing of note is a slight pulley/bearing whine, although none of the pulleys seem to have any play and the fan belt doesn't appear to be slipping.

Would anyone have any further advice or input, all advise gratefully received, going to have to try to sort this on a shoe string as funds are critically low!

Thanks