Idleing problems with 93 Paseo

[sportsaholic07]

My 93 Paseo lately has been having problems idleing......after warming up for about 3 mins it starts to rev itself to about 18000rpms and then it stops revving back down to about 1200rpms it fluxuates like this for about another 5 mins and then is good.
Any ideas why?

Thanks in advance
Sportsaholic07

[4agetercel]

car may be low on coolant my tercel did that because there wasnt enough in it last winter

[sportsaholic07]

Thanks for the idea,

I went out and checked, but no luck, coolant has plenty in it.


Any other ideas?

[4agetercel]

only other thing i can think of is a sensor in the throttle body or a vacuum hose that has fallen off

[Dhavut]

probably a vaccum leak somewhere most likely........ my tercel with a paseo engine had a vaccum leak but it constantly revved high and low and din't go away until i blocked the vaccum leak.......... then it ran fine......... maybe vaccum hose came off somewhere... look around i guess

[Paseo15psi]

I would check the thermostat and the water temp sensors.

[Mike Kamm]

If you found the problem, please let us know what is was. My '93 is doing the same thing, but I caused it somehow. I did an automatic to manual swap and now I have the same idle fluctuation during warm up. I bled the cooling system properly and checked all of the vacuum hoses twice.

[sportsaholic07]

I figured it out a little while ago....It was low on coolant, the radiator cap is not working properly so when it over flows when the engine heats up it does not draw the liduid back in when it cools down.......i put some more coolant in and it works fine now