Remove the air cleaner and check to make sure the throttle plates are closing, I have found many different things that can keep the throttle from returning all the way. IAC is a possiblity but most of the time they stick out which give a low or rough idle. TPS againhave not found on to be the cause of high idle a lot of other problems. Vaccumn leak can give you a high idle but find most of the time they just give you a rough idle but you should be able to hear the leak. The spot where the leaks are most apt. to be found is over by the EGR valve the heat from the EGR valve will just bake the gasket and make it brittle and fall apart, just give it a squirt of oil with the engine running and see if the idle changes, you may even see the oil sucked in. You do need to remove the air cleaner assembly plugging the thermac vaccum port and start the car and see what happens when you start the car, watch the spray coming out of the injectors, if it's real heavy you may have to take a look at the coolant sensor, if you hace a round connector going to the coolant sensor you need to replace it with the two pin sensor the original barrel sensor had a real problem with poor connections that will throw off the readings and most of the time fool it into thinking it's much coolder then it is and dump a lot of fuel. But also with it idling if it is still high and you can see the throttle plates are closed then just look for the IAC pintels and see if they are retracted or extended. If extended as if trying to slow down the engine then you will need to look for leaks. If it's retarcted a lot then you have to suspect that for some reason the ECM is comanding the high idle then you will have to look at sensors and or ECM. But I think you will find something holding the throttle open, but check it out and let us know.
David Fulcher