Marcos Maniacs

Hi Guys,

I have a May 1996 Mantara with a fuel injected Rover 3.9L V8 - known 
as a 'Serpentine' engine I believe.

I have an intermittent problem with the engine idling. Every so often 
(about one trip in six) the engine will not idle - it just stalls eg. 
when pulling up at a junction, the normal running gets very rough and 
the fuel consumption goes through the roof. This usually lasts for 
about 20 minutes before it clears. It can sometimes be cleared by 
restarting the engine (but not always). It can occur from cold or 
come on when hot.

I have cleaned the plenum chamber/butterfly, and cleaned and tested 
the idle stepper motor/valve. The engine is in good condition and 
otherwise in good tune.

This is a fuel injected engine with an ECU (I think it's the same as 
the one fitted to the Range Rover V8) so there is no manual idle 
speed adjustment, just an idle bleed screw - the setting I have 
checked as OK.

I have had the car eight years (from new) and this problem has always 
been there.

I am told one likely possibility is the temperature sensor for the 
automatic choke going intermittently faulty and causing the ECU to 
deliver a really rich mixture.

Does anybody have any other ideas?

It's about time I sorted this one out!!!!

Best regards.

Mark.
Worcester, England