325i running high

[mrs14]

My 1990 325i sport is running a bit high,
when i start it first thing in the morning
it sits and ticks over at about 1300rpm
and if i take it for a good drive it
comes down a bit but still sits at about
1000rpm, anyone any ideas

[Speedtouch]

Check the blue temperature sensor resistance at the ECU socket:

http://www.e30zone.net/e30zonewiki/inde ... emp_Sensor

Also check that the throttle position switch (TPS) is clean and working correctly - this tells the ECU when the throttle is closed so it switches to the idle map.

http://www.e30zone.net/e30zonewiki/inde ... ion_Switch