Right, here goes...BMW 316i, 1990 M40 engine - when I picked the car up about 3 months ago the seller said it had a dodgy idle but he'd set the mixture and got it right. It was ok for a while but one night I filled the tank up and as soon as I started the engine the idle went insane, straight upto about 1200 and then down to 500ish, repeatedly...I drove off and everytime I came to idle it did the same (drove ok though, but not perfect, bit of a miss-fire). AFter 5 mins or so it started stalling every time I stopped to idle, but started up again ok and this continued till I got home.
Next day, car wouldn't start. A week or so later I called my regular mechanic out and he sent an auto-electrician, who said the car was over-fueling, changed the blue temp sender and put new plugs on, got it running and took it in too have a good look at. 1 week later, car was running but still had same idle problem.
I then took it to my usual mechanic, who cleaned the ICV up, which made a huge difference, and as he was going on holiday told me to try and get hold of a good AFM as the one on the car was knackered (turning the screw was having no effect so it couldn't be adjusted, and he reckoned it was running too slow). I got a working AFm (cheers Chris). put it on and all seemed well. The idle speed was way too fast (1300 ish), which I was going to leave until my mechanic got back from his hol as I didn't want to mess around with the screw myself.
Anyway, went out in the car a few times, all's well (apart from high idle with a slight missfire which I hoped might be down to the idle speed).
I've just been to put some petrol in the car again and IT'S ALL GONE DAFT AGAIN! Same idle problem as before, all over the place and very nearly (but not quite) stalling at idle (and when changing down in the lower gears).
Has anybody got any idea what's going on because I'm at my wits end and will be torching the b@stard thing soon!!!!
(I hope this all makes sense, I'm fuming but trying to type coherently!)
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