over reving sporty


my sporty has suddenly decided to idle rev at 2000 rpm. runs fine when driving but increases when sat at traffic lights etc, even after a long run. no mechanical changes to the sporty in the last six months apart from oil change and spark plugs. anybody got any suggestions?

over rev

i have a good mate who is a gr8 mechanic ... he chats to me about stuff as he knows I am interested to learn ... he has spoken about problems such as yours, and explained that the more modern engines have the following sensors , usually towards the upper part of the engine, which can be located, removed without too much trouble, cleaned ( with petrol & much rubbing!!) and replaced.

Idle Valve - as name suggests, this dictates the Idle speed of the engine, at idle!

Throttle Position Switch - this detects how much your accelerator is being pressed down : if faulty / dirty it will give a false reading & send the wrong message to your ECU, which will then rev up the engine too much !!!

The above apparently will usually cure things - maybe permanently - maybe for a few months: If the latter, then the component itself is getting to the end of its usable life & will need replacement!!

if the car has a Carb, then clean & lubricate the linkages around the carb - accelerator cable & choke components ... and ensure that the idling Adjustment Screw has not vibrated itself out of position !

If the car has an automatic Choke, then locate the Auto Choke unit & clean as per above!!

Hope that helps!!!

over revving sporty

thanks for those suggestions will definetley try them.
Took it to a daihatsu garage they said it was a worn throttle body valve and would cost in the region of £300. You can imagine my response, "F*** THAT!"