Thread: idle problems

Most probably a sticky stepper motor. So clean the stepper.

But could be that the centrifugal advance is sticking and not retarding as speed comes down. In this case remove the dizzy cap, rotor and oil inside the shaft. Be VERY careful removing the rotor in a way that does not lift the shaft, as if the servicing has been so neglected that the shaft ois sticking, the rotor may be stuck on. In that case it is better to break the rotor into bits rather than break the clip on the shaft.
Regards Philip A

Tony, as Phillip said clean the stepper first - lot easier.
This is how to do it:

6) Stepper motor - usual advice is to whip it out and give it a clean with carby spray. However I think this is possibly the better way(?)
a) unscrew it from the plenum and reconnect the multi pin. put it into a clear plastic bag with an elastic band around the cable
b) stuff a large rag into the hole in the plenum ie one that won't get sucked in. Or get wrapped around pulleys - take care.
c) Start the engine. Revs will soar to around 2000. If it doesn't start adjust the rag to limit airflow. The ECU will activate the stepper motor and the plunger will be driven out of the housing. It may take a couple of start stops but the plunger and spring should fall into the bag - a gentle wiggle to assist may help.
d) carefully clean the threads, plunger and key way and relube. Don't use anything heavy like copper grease or lithium. I used a bicycle silicone chain lube called "ICE" and it's worked spot on for ages.
e) screw the thread back into the worm - trick bit as you need to align the keyway - it's a feel thing. flip the ignition on and off a few time (no start) to confirm ok, then put it all back together.