carb change related questions

[black87yj]

I hooked up a motorcraft 2150 and my jeep idles and runs 95% better. so whats the problem ? when i step on the brake the idle drops 3 grand, if i mash the brake 5 grand. what might cause this ? I have read page after page of vacuume diagrams and the one that worked best left the egr off and ported the fuel tank overfloe from the canister to the egr tee at the manifold. even if i cap all the ports it acts the same ? anybody have this happen ?
thanks for any help in advance !

 

[lah2420]

What's it idle at? Mine is only around 750 rpm. I don't understand the 3 grand and 5 grand.

By it dropping with the brake stepped on, have you disconnected the hose going to the brake booster and plugged it to see if that's your leak?

 

[black87yj]

idles at 900 to 1000 rpm (grand) i got typing to fast and forgot to use rpm after it dropped from a grand at idle ..oops it drops from 1000 rpm to 500 rpm when on the brake and to 200 rpm when i stand on it. i'll try the booster vac plug today. thanks for the tip.