Hey zukipilot, this sounds like it could be your fix. It works for 1.3 tbi and 1.6 tbi. I know it worked for 2 people.  For the 16 valve I don't think this applys. Sorry.  Jeff
This is not my fix. It is something that I had saved from the Off-Road BBS.
I was tired of the 2-3000 rpm high idle and intermitant surging as engine warmed up. The fix is great-non perminant takes about 10 minutes and best of all costs little or nothing.
So far, engine and ECM seem to be working wonderfully.
Cold start this morning at 22 Deg. was great-----Engine fired first time and ran at 700 rpm until warm. Took a little longer to warm up than at 3000 rpm. Just think of all the fuel savings.
You need a piece of rubber tubing the same diamater as is used between the radiator and the overflow bottle. Cut off a piece about 1" long and insert a 3/4" long bolt that fits tightly into the tubing----all the way to the head.---Make sure that it fits tightly enough that no air or vaccum can pass through.
On the front of the throttle body--Passenger side----There is a cover plate with three screws on it.
Remove the plate.
Inside the hole, there is the infamous wax pellet that generally causes the surging problems.
This is the thermal valve that is operated by the temp of the antifreeze. When the antifreeze is cold, the pellet is cold and therefore, contracted. This lets a controled amount of air into the tb that is not metered by the butterfly. This extra air is what raises the idle. As the antifreeze warms up, the pellet expands and is supposed to slowly seal this intentionally created vaccum leak. This is supposed to slowly lower the idle.
Inside this cavity, there is a ring with several raised bumps around the surface. There is a hole in the side of this cavity that goes directly into the manifold. This is the hole that I plugged with the rubber tube and bolt. If the ring with bumps is in the way, take a sharp flat head screw driver and using the bumps, screw the ring in until it is far enough in that the vaccum hole is clear. Firmly insert rubber into hole---Make sure there is a GOOD seal or this will not work