Brake cleaner sucks for finding vacuum leaks! Use a propane soldering torch on high and you can direct to a very small area.
Surging is usually a vacuum leak. Other things that can do this on stock motor and tune is throttle blades to far closed. You can turn in throttle stop screw 1/4 turn and then start vehicle to rule this out. Do not do anything else with this screw, it does not set idle!
The hose going to air filter is air coming into engine, there should be another hose off TBI to PCV valve that sucks in air.
Your MAP sensor should be connected to tube in center/rear of TBI unit between fuel lines. Good stiff hose so it does not collaspe.
Post a picture or 2 of engine and conversion stuff and we can spot issues!
Your really going to need data so look into a cable from Robert.
http://www.gearhead-efi.com/Fuel-Inj...uy-ALDL-Cables!
TunerPro RT software is $39.
http://www.tunerpro.net/downloadApp.htm
ADX and XDF files for TunerPRo RT are free for all OBDI vehicles, your's are here:
http://www.gearhead-efi.com/Fuel-Inj...Information-42