Vitara mk1 throttle Opener test

[Ade316]

Hi I have been testing components on my SPI unit as I feel the car is a bit hesitant on acceleration and have found that when I change gear the revs don't drop as quickly as they should when the clutch is depressed. I am following the tests in the Haynes manual. For the throttle opener test it says I should disconnect the vacuum hose and expect to see rpm rise to 1700-1800. When I disconnect the hose and plug it then switch on, the rpm initially raises to about 2400 then quickly drops but it cycles from 1500 to 2000 rpm every few seconds rather than holding a steady rpm. The throttle opener works ok I have tested it with a vacuum pump. Do these symptoms indicate what my problem could be?


Thanks very much
Ade

[Rhinoman]

As far as I know the throttle opener only usually activates when its very cold, I've never seen one switch on, its something I've never got round to looking at in any detail. With the throttle opener activated the ECU won't be able to hold idle under normal conditions so it will hunt about. It sounds like the TO is working properly.
I would check the compression and if that's good give it a full service, does the Check Engine Light come on at key on and then go off again when it starts?