Erratic Idle Speed

[Guest Barry Garlow]

Hello, I'm new here.

I'm having some problems with the idle speed on my early 1989 Corolla 1.3. When the idle speed is set to correct RPM, it slows up at regular intervals and returns to normal.

Any help would be appreciated, thanks.

[bigshark]

has d spark plug been changed recently?

[Guest Barry Garlow]

Thanks for the reply and yes, the spark plugs have been changed since the problem started.

[karmacode]

Thanks for the reply and yes, the spark plugs have been changed since the problem started.

hey there, im no engine know it all but that started happening to my 1999 corolla, the revs dropped down..car was shaking cause the revs where so low, i said to my dad his first thing to check where the spark plugs and they where ok.

he took it to work and done a compression check on the cyclinders. cyclinder 4 was not fireing properly, hes in the process of taking the engine apart, he thinks its a burnt out valve or something....i dunno..get the cylinders checked??

let me know how u get on dude.

[hedleyf]

Hi,

Will need more info on the engine type and is it using a carb or injected,I would not be taking the engine down at this stage,to imply that the valve is damaged would mean that the engine would missfire.It sounds more a problem with idle control,post your engine code.

Thanks for the reply and yes, the spark plugs have been changed since the problem started.

[Guest Barry Garlow]

Thanks for the advice. Problem turned out to be just a split vacuum pipe. Thanks again, Barry.