SpoonyGT

First, I already did a huge search on MF and other sites.

This is step-by-step what has occurred:

1. Got an aftermarklet plenum bny Grantanelli and installed it. I used the stock gaskets because they were still intact.
2. Started the car up and it idled at 2000rpms. Drove it a little never went down. Uplug the battery terminals for 30minutes and still no help with iudle.
3. reinstalled the stock plenum on the car and the idle was still high. Checked all vacum lines and no leaks. It sounds like more ai is around the plenum tho.
4. Bought a new TPS and IAC valve as I got codes P1504, P1506, and P0120.
5. The TPS and IAC helped idle a little bit it is now around 1700rpms.
6. Swapped the after market plenum unit onto the car and still same rpms.
7. I adjusted the idle via programmer down to the minimum and it has gone down to 1100 but wavers up to 1800 and sometimes 3000.

So, It's not the TPS, not the IAC, im getting a P0120 code still.
Idle is still at 1500-1800 rpms.

When I backed off the idler screw, the hgammer wouldn't go backl any farther...
there is also slack in the accelerator cable (the exposed cable) on the linkage. Should thios be tight or tought?
Also, the butterflyu valvbe in the Throttle body should be straight up and down or at a slight angle???

Help is appreciated I'm going out of mind with the idle. Luckily, the car is going in for body work this week so it will be in a garage and I have a second mode of transportation.

Only things I could think of doiung:

-Replace vacum lines
-Replace PCV Valve
-Replace throttle body gasket (made a new one out of gasket material)
-Replace lower intake to plenum gasket.

Thanks for the help!