engine idle when brake depressed- help!

I have a 93 toyota, it runs great but when the engine is warm and I have my foot on the brake the idle drops and raises continually. I hope this makes sense, anybody have any suggestions?

My other toyota was like this also, I was hoping it was a common problem. anybody?

It has to do with vacum, check for leaks in all the vacum lines.

vacuum booster is leaking

I checked for vacuum leaks and didnt find any. It only happens when truck is warm, thats why its throwing me off, how can I be sure it is the booster? if I were to replace booster is there a smaller booster from a different vehicle?

Sounds like the booster. you can replace it with a brake booster off of an 84-88 toyota automatic truck. Those boosters are smaller than the manual transmission ones.

thanks I'll try that then.

When you depress the brake pedal if you hear air blowing then it is for sure your vacuum brake booster

I had the same problem on my 89 4wd and the TPS was bad changed it and fixed all my problems

this may sound really odd my toyota did that while low on coolant. yes coolant when i had a leaky water pump i would notice that when i depressed the brake at a stoplight the rpm would race or nearly die erraticly. hope this is any help