My 99 passatdoesnothaveanypowerat1100rpm.

Too much fuel, not enough fuel Both will do it. Have the codes read. Other mechanical things can do it also. valves..

It's under the throttlebody you will have to take the throttlebody off and it will be mounted with two bolts on the bottom of the throttlebody with three wires comin out of it connecting into other relays.

on the throttlebody ( where the air intake hose connects to the throttlebody, opposite side of cables )

it is located right below the throttlebody where the air inlet is below the wire harness

check the air bypass valve on the throttlebody at the air inlet try tapping on it and see if it will idle ok

the ecm fuse is blown

Check the injector pulse. Used noid light connected to the injector connector. Crank the engine and observe the light flash.

Quite often if no codes are coming up & stalling like that , especially under load conditions, such as AC on etc., it a dirty IAC valve. Chrysler used to call them AIS motors, (automatic idle speed ) Get a can of throttlebody spray cleaner, and remove the IAC, spray the pintle (pointed part) & shaft, to clean it off & spray port good that it came out of, then re-install & give it a try. If it cures it then starts to act up again later, replace it.

The IAT sensor should be located in the air inlet tube to the throttlebody

you are getting a misfire and 99% of the time you need a tune up
plugs and wires and clean your throttlebody