88 4Runner High and ERRATIC IDLE

My brain hurts from trying to solve this problem...PLEASE HELP ME. I am having two possibly related idle problems with my 88 V6 4Runner.

1st) It used to idle at 800 rpms which is perfect and then when winter hit it decided to start idling at 1500 rpm. If I let it idle for about 20 mins it will come down but as soon as I drive, it goes right back up.

2nd) when the brake pedal is depressed my idle hunts from 1000-1500 rpms. And for some reason when I engage the 4wd the idle hunting stops.

If anyone can solve one or both of these problems or offer any input it would be greatly appreciated.

Thanks for your help

Cory

Reply to
FriendlyFire19
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decided to start idling at 1500 rpm. If I let it idle for about 20 mins it will come down but as soon as I drive, it goes right back up.

for some reason when I engage the 4wd the idle hunting stops.

be greatly appreciated.

The second problem is a symptom of the idle being too high, so fix the idle speed and the brake cutout problem will fix itself. Sounds like some of the cold start compoents are bad, check the temp sensors and cold start air valves and injectors to see what is wrong.

Reply to
Roger Brown

it decided to start idling at 1500 rpm. If I let it idle for about 20 mins it will come down but as soon as I drive, it goes right back up.

And for some reason when I engage the 4wd the idle hunting stops.

would be greatly appreciated.

Reply to
Ivistar

Hi Roger

I took your advice and cheked some of the cold start components and everything checks out. Although I do not know how to check the cold start vavles. How do I do this???

Idle Adjustment

My truck idle was perfect for the past year and I never had to touch it. Then it sky rocketed to 1500 from 800. can lowering the idle possibly pose a problem. Because the truck does on very rare occasions idle the way it should, but only when it is idled for a long time and not driven.

I appereciate the input very much.

Thanks

Cory

Reply to
FriendlyFire19

Hi

I took your advice and checked the vacuum pressure and it fell right within range.

Any other ideas???

Thanks alot for your input

Cory

Reply to
FriendlyFire19

Low on coolant? Anything to raise the idle, is base idle will make it go high,then into fuel cut, sropping it back down.

Reply to
MDT Tech®

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