I am a newbie so please dont flame me.
My son purchased a 1998 Z24 2.4ltr. It had a hole in the block so we purchased a used engine. I just finished up swapping the engines and am having some issues.
When i start the car it goes straight to 3-4k rpm. I have swapped the AIC, EGR, TPS. Nothing changes the rpm's. I have pulled the AIC to examine the pintle, it appears to be coming out all the way (.633) @5/8inch. If I unplug the AIC the rpm's increase to @5k. I have plugged the AIC port with a dowel and tape to ensure a good seal. No change. I have fabricated a shim plate for the EGR to check if I was leaking past. No change. Yes the butterfly is closing all the way. The only thing I have recently discovered is that if I unplug the pressure sensor (+5v reference, out, and ground) from the throttle body the rpm's do drop to @900-1000 rpm's. But it runs like a$$, almost like it is missing real bad. I'm going to exchange the throttle body and change plugs after i get off work. Any other suggestions. I really need some help.

Thanks in advance-
Chris

Poor some water onto the intake manifold, where the manifold meets the head... if it wants to stall, you have a leak, take the manifold back off and redo it, I use gasket maker material to seal it up real good.

even though the throttle closes completely. look around the butterfly and see if it completely seals around. i have and 2.3 throttle body whos butterfly had mabe a 1-2mm space between the top of the fly and the throttle body housing

Thanks for the replies. I will try both suggestions. I have pored Sea Foam into the TB and it stayed in quite a while, it's staying closed pert good.
What does that pressure sensor measure? I presume it is TB vacuum. It's strange that it would run better w/o it hooked up.
Now for a really dumb question . Would it matter that the engine is out of a automatic? I would say "no" but then I make a living out of being wrong. I had to exchange the flywheels from the two engines.

Aside from the flex plate (auto) and flywheel (manual), the engine is identical between auto and manual tranmissions. Doesn't make a difference.

The MAP sensor reads the Manifold Air Pressure. There should be a little rubber hose connected between it and the side of the intake manifold. It's common for that hose to rot out and crack. Could be causing the high idle... something to check. Perhaps the sensor is bad... swap on the one from the old engine and see if it changes anything.

Did you remove the intake manifold itself when you put the engine in? Make sure the gasket is ok between the manifold and the head if so...

Thanks all for the replies. I ended up swapping the intake, throttle body, injectors, and EGR tube. One of them was faulty. my guess is with the intake. Thanks again.