Corolla Revs/Idles up and down when cold

anneo · 31-01-2011 11:48am #1

Hi,
Can anyone help me. I am trying to find out why our corolla 97, 1.3 keeps revving up and down when its cold, there is low miles on it.
When you start it a leave it ticking over, the revs go from for example 700 to 1500 to 700 to 1500 to 700 and so on. And it seems ok when its warm.
Any help appricated

Thanks

glenb0 · 31-01-2011 8:12pm

It sounds like there is a problem with the automatic choke. Your car should idle at about 1500rpm when cold as the auto choke is engaged. Then once the engine reaches a certain temperature, it should disengage and drop to between 650-750rpm. You do mention it has low milage and is nearly 14 years old. I would probably recommend getting your mechanic to give the throttle body a good cleaning out. That may help

anneo · 01-02-2011 2:08pm

Thanks for the reply.

mickdw · 01-02-2011 3:21pm

It quite possibly a cracked hose on the air intake side of the engine.
It the engine is getting air that is not metred, it will cause this.

taintabird · 01-02-2011 4:16pm

like above a cracked hose causing an air leak or your ydel air control valve could be acting up either

Corolla Revs/Idles up and down when cold

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