Weirdness!!

[mikey2]

Things were going well, until the coolant temp sensor failed, so i changed it, now, its leaking coolant from the bottom pipe from the rad, bad enough for it to dump the lot just now. I didnt think it was that bad, but seems its failed totally now!!
If that wasnt bad enough, i think i am gonna have to change the turbo again, back to the td05, joy.
However, the weirdness, which i dont know anything about, is the fact that for starters it takes ages to warm up, then suddenly it just goes to normal temps after showing cold for longer than normal, while its warm, it behaves as you would expect, but, when its cold, its weird, the idle is higher than normal, around 2k, and persistent enough to keep the car in motion at 2k in the lower gears, but, really weirdly, if i am stationary, the idle will drop slowly as normal (ish) but, if i take it out of gear, the revs rise again, then drop off, if i put it back in gear, the revs go back up again, then drop off!! all this time i have my foot on the brake, well away from the accelerator!!!!!!
I specifically tested to see if it was me, and i did nothing, i didnt move apart from to take it in and out of gear, so i all i had was my foot on the clutch and on the brake, specifically well away from the loud pedal!!??

Anyone experienced similar??
the exhaust is leaking, that i know, i am not sure where from yet, but i suspect i did something on an 'energetic' standing start (i had to pull into fast moving traffic, in the fast lane) ever since then, its not been right, the turbo sounds bad at higher boost (1bar+) like a farty type sound, only ever on boost!!
I am gonna change the turbo and associated gaskets next weekend anyway, and i may get rid of the d/v as i dont think its holding the pressure too well.

Anyone had a similar experience???

Ta