Hi. I have a pulsating idle. It starts as the engine warms up, at roughly 70-75 degress. The pulsating is perfectly rhythmic at 2 seconds high 2 seconds low 550 - 750. Then gets more pronounced the hotter the engine becomes upto the point when the rad fan comes on when the rpm has risen to approximately 950 to 1000k. When the rad fan comes on the rpm becomes steady at about 650. When the engine has cooled a bit and the fan goes off and the pulsating recommences. It's almost like the idle rpm is being governed by the signal from the 02 sensor...0.1 volts is low rpm and 0.8 volts is high rpm.

Another way to even out the idle rpm is to unplug the pre cat 02 sensor. This obviously triggers the EML but the rpm sits at about 650. Plug the sensor in and there's a bit of a delay of about 30 seconds and the pulsating returns. But I have to drive the car for a few miles before the ECU twiggs that the sensor and the EML goes out.

The car drives fine apart from trying to reverse up a hill when I can't hold the rpm. However, when I hold the rpm at 2K then intern switch on first the heated rear window, then the sidelights, then cabin heater the rpm drops to 1K.

A couple of days ago the car stalled whilst on idle. No ECU lights on the dash, checked the fuses and an ecu one had blown. Replaced it ,turned ignition on and the coilpack started to smoke.

Any ideas please?

Thanks in advance.

Dave