Idling problems.

[Toyocel]

My 87 tercel 4wd auto revs high for a few seconds then low for a few seconds. It does this when I first start the engine for 5-8 minutes and only does it while in neutral. Any ideas as to what's wrong? I'm into cars but I don't know a lot sadly. Thanks!

[Petros]

you might check for a vacuum leak, search the archives on how to do that. Vacuum leaks will cause the idle to "hunt" up and down. Usually an easy fix.

Also there are a number of cold start devices on the carb, if you go to the Service Manual there is a list of symtoms and what to check, usually you can narrow it down pretty quick once you know what to check. Sometimes you can even by-pass the bad device if it can not easily be repaired, and live with it.

Where are you located?

Good luck

[Toyocel]

Thanks for the tips I'll check it out tommorow morning. I am located in the middle of the Canadian prairies. Gets quite cold here!

[emmahumpfritter]

I visit my two good friends up in Spiritwood Sask. quite often. Near there? I'll be heading to Ness Creek Festival in July as well... Beautiful (and underappreciated) country up there. Friendly people too.

Brenton

[Toyocel]

Regina, the city that rhymes with fun.

[tercelwill]

If it only does it cold I would consider it normal. My warm up has always been a little erratic but it just doesn't seem worth it to spend hours in the FSM to figure it out.

[Toyocel]

I had it in the shop for 2 weeks started it up and the idling was rough, im going to clean the carb and see if that helps.

[4wdchico]

First thing I would do is to pull the hose off the nipple on the the AAP diaphragm cover. It is located on the right side of the carb, just behind the front right corner of the carb. If the inside of the hose is wet with gas, your AAP diaphragm is breached and can cause very similar symptoms to what you are describing. Raw gas gets into the vac system and runs amok, not pretty. Then the TVSV warms up enough to turn off the vac to the AAP system and most of the symptoms go away. I say most as raw gas in the vac system can cause the hoses, diaphragms & even the the TVSV to fail quickly...