2.7 high and or rough idle

My 2001 Intrepid ran good before I removed the intake air plenum. I removed the plenum to replace the air coolant bleeder. When the plenum was removed, I left the throttle body connected and just unhooked the wires from the idle air controller (IAC) and throttle position sensor (TPS). After reassembling the intake, the car was idling up around 4000-4500 RPM. The idle is really rough as though it is hitting a rev limiter. When I unhook the TPS, the car idles around 1500-2000 RPM but still acts like it is hitting a rev limiter. Any thoughts on what might be causing this? I don't know why lifting the plenum and throttle body would wreck either of the two sensors. I also can't figure out why the car idles so much lower when the TPS is unhooked. Would that suggest the TPS needs to be replaced? The throttle is operating freely and is fully closed when I'm attempting to start the car. I'm stumped and running out of patience.

So I tried a new throttle positon sensor. The new sensor acted exactly the same as the old sensor. Runs fast when it's connected, slower but still not right when it's unhooked.
Help!!

You have a vacuum leak more than likely. Check the EGR tubes.

yup the egr tube in the rear of the manifold has a rubber seal, possibly it's torn or fell out

I finally got it fixed. Thanks for the replies. I replaced the idle air controller motor....but I'm not sure that had anything to do with it. I replaced the intake manifold gaskets, the old ones were worn and significantly thinner than the new ones I put it. I think air was being drawn in past the gaskets. I also found a large vacuum hose on the top of the manifold with a crack in the hose. Although I'm sure this didn't help things, the car ran noticeably better after replacing the gaskets with the vacuum hose still completely disconnected. Got everything replaced and back together and the car runs perfect again. The dash light even went off after a few on/off cycles of the car.

Thanks again.

I have a 1990 ford f250 4x4.
I reverse no problem .I drive off the same ..Except ,when i get on the freeway .I can hear that my transmission is not changing gears . Once i get to 55mph.
I could feel it forcing it self..:runaround: any suggestion!! will wait for your reply ..
Thank you
cjr

Thread jacking man. I will tell ya check the vaccum line that goes to the transmission. Also I would check the transmission level.