I have a 1990 v6 4x4 4runner. I'm in dallas tx and last week it's been a bit cold in the morning, around 55º. well, my engine reves up high around 1700 rpm and stays there for 10 mins of driving. My power steering pump also makes a noise for about 10 mins. after the truck is nice and warm eveything is fine, no noise and the engine idles fine. today it was abot 85º when i turned on the truck for the first time in the day and the idled was up to 1100 rpm and then it when down to 900 after may be 2 mins. The power steering pump didn't make any nosie. before it started to get cold the truck would idle fine and the pump wouldn't make any nosie. I just changed my spark plugs, wires, cap, rotor, 02 sensor, air filter, fuel filter, i've cleaned my intake. I checked the steering pump fluid when the day is cold and it's making that nosie it looks like foam in there. when the day is warm it looks fine. Why is the engine revving so high, I try to keep it tuned and she runs very nice. I can't even feel the engine on once its warm. i can understand the pump is getting old and it may need to get warm to work.

 

when there cold it will idle high till it warms up its fine as far as the steering pump i dont know about that some one will chime in

 

new cars don't idle like when its cold. they do it for about 1 min or less. I also have a 2003 chevy silverado 1500, and when its cold it will rev high for maybe a 1 min even less than the idle will go down to 500. I know that when car become older they need repair and tuning, so i thinking maybe some thing needs to replace or to be tuned to get the truck to idle right.

 

Foam in the ps fluid reservoir would make me think you've got air in the system. Is the fluid level low?

I just replaced the pump on my 95 - It would be terribly noisy when the fluid got real low, especially at startup...