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My son has a 1991 2.0L Corona, carburettor model.

Every now and then when he turns the key off the engine continues to run as if it's on 2 or 3 cylinders.

Any ideas on what might cause this?

John

From the "Ask Jack" archives - 19 September 2009

In a lot of cases it is because the engine idle speed is too high when the ignition is switched off.

Try loading up the engine a little to drop the engine revs before you switch off.

Having a carburettor means adjustments should be easy to make.

If it has an automatic choke, there may be a problem in this area causing a fast idle.

Its always a good idea to check all the basic tuning components at the same time.

The combustion chamber may have a heavy build up of carbon creating hot spots which can cause the running on, but make sure the basic tuning settings are OK before you go down other more expensive roads.