look at the grounding-connection on the back of the UIM, where you would mount an engine damper.
there is the grounding wire from the engine/ECU-wiring connected with the short 7" wire to the chassis.
Look if the skrew is tight enough..
or look for any other grounding-spot on the car.
I had the same problem.
felt like a fuel-cut... it was only this connection between those two wires.
the vibrations of my engine-damper loosened the wkrew and so the two wires had no perfect connection.
after refastening the skrew everything was perfect!!
look: here you can see the grouding wire to the chassis. on the upper right of the picture you can see the mount (has a yellow dot on it!)