1991 Tercel Idle Surge

[Bettendorf]

My 1991 Tercel has had this idling problem ever since it overheated. I was driving down the freeway one day and the bolt fell out of the main pulley - I ended up with a hole in the radiator, so I replaced the radiator and everything was fine. It doesn't surge all the time at idle - it is pretty intermittent. I will pull up to a stop light and it will do it and then at the next stoplight it won't do it. And the RPMs vary - sometimes it will go from 1200 up to 1800 and sometimes from 1800 up to 2200.

I replace the water temp sensor and thermostat last night hoping that would solve the problem. The car still does it... I have checked the fault codes and there are none stored in memory?

What is the next thing to check? I have checked all of the vaccum lines for leaks and there are none.

It has a 5 speed manual transmission.

Thanks,
Jeff

[Bettendorf]

I ran a some Seafoam throught the vacuum line going to the PCV. The engine runs so much better now! It actually idles very nicely - about 850 rpm after it is warmed up. What do you all think the problem was? I am sure something was gunked up.

What is the name of that short hose that goes from the throttle body to the valve cover? Not the one to the PCV. And, can I get that at any dealership?

Thanks again!
Jeff

[Bettendorf]

Hmm... Now it is idling bad again. up and down... up and down! Does anyone have any suggestions?

Thanks,
Jeff