Months of tickety-boo to chaos in 5 minutes.

[Connieblau]

320i convertible 1/4 million miles, most by my wife. Spent a couple of years tidying cleaning some paint, last problem solved was months ago, cold engine start jumping straight to 2,300 revs. Fixed this by replacing throttle sensor. After six months of complete normality, even instant idle at 7.500 rpm. Went shopping 5 miles away. Came home , dipped beam warning light showing.
Five minutes later, shopping bags indoors, car starts at idle. Dipped beam sensor still lit, also Washer Fluid and Coolant . ALSO LIT are all four indicator lamps, but not blinking and switching on the indicator stalk itself started the nearside main beam headlight blinking but not the driver side. We put it into the garage, turned everything off. After a cuppa indoors I spent an hour taking out the lighting switches to check for a loose wire. Fat chance. Switched the ignition back on, left the engine turned off and checked through the switches. This time side lights are ok, indicators are ok dipped beam ok, high intensity ok. High beam switched on but started to 'pulse' drifting on/off every five seconds or so.
Today ignition on engine off, all lights working, no warning lights. Everything ok even when all on together, until dipped beam and main beam disappear slowly. Thought I'd try everything with the engine running, idle climbed from cold to 2,000 revs over about a minute! I have a Peake Research R5 FCX3 (for BMW) scan reset tool so I plugged this in - it showed 'Fc' and then it went to '--' (reset all clear) but the car still starts on high idle. Battery is only months old. Summer.'s coming ideas please. Trevor Moore

[Connieblau]

Dividing this chaos into two halves, the first has been an earth problem, the earth connector behind the nearside headlight was fixed down tight, there was a 'nipped' cable not too far away, so that was easy. Amazing how the car has been faultless for months,, it was hanging on a thread. The engine thing that happened at the same moment has got even more confusing (for me anyway). Yet again I have spent some time looking for leaks, checking current at the ICV , TPS 'clicks' the blue sensor is new, Ive kept the driver's window wound down, battery is over 12 volts. I have even cleaned the track inside the air filter box of tricks. The air filter connector I attempted to test with the multi-meter but I struggled to find any advice on what any readings might be. The mechanisms inside the afm 'box' have not been touched since the car was made. So, today, it started easy and went to 1,000rpm for about 3 minutes., normal until it then went to 2,000rpm.
I took off the connector to the ICV, revs dropped slightly, went back up when re-connected. Took off the connector to the air intake.
Revs dropped to almost STOP, but kept going at about 400rpm, CHUGGING like the govenor on a petrol lawn mower. Ran for 1/2 minute turned it off. .??? Started it again wasn't difficult, chugging again, seems to smell now. Started it again still chugging but revving very slightly up. Do I have an Air intake problem?
On the day of the initial 'major' incident (in hindsight) we had hit a serious pot-hole on the way home that had lit the 'low beam' warning light on the check board . Easy to connect that with the earth fault,
Looking through E30 idling problems, chugging is quite rare. Trevor Moore.

[Contours]

I see that my own car has started to idle slightly too high at start up since getting a new back box fitted to the exhaust. With all the rain here I haven't had time to check it out but it is getting too much air from somewhere causing it to rev a bit so I would be looking for a vacuum leak to start with.

[Connieblau]

I wonder if the 5 times thing is happening. Does the computer reset itself after 5 starts? , today it started straight away, chugged along for a few seconds, revs climbed to exactly 1,000rpm warmed up , settled at 760rpm. It now has flat spot when hot, I don't remember any flat spot in 25 years of ownership. Getting there?