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Just checked to see if i was out of fluid, but its full.

Any other ideas?

Thanks for the ideas so far!!


As noted above, idle speed is too high. I can exactly duplicate that issue if I turn my idle speed up to 1000-1100, then hitting the brake causes the loping idle. Turn the idle back down around 800 and all is fine. Also, check the TPS idle setting:
- http://www.4crawler.com/4x4/CheapTricks/TPS/index.shtml

You can rule out the brake booster by plugging the vacuum line to the booster temporarily and if the problem remains, it is not the booster, but if the problem vanishes, it is likely a vacuum leak in the booster.