Your issue is not the IAC if a new one was installed. Plus you can see the bouncing rpm showing the IAC trying to adjust.

What are the wire colors going to the MAP sensor and the wire colors to the throttle position sensor? The TPS should have grn/blu, red/blk, and yel/blu. The MAP has yel/wht, grn/wht, and wht, yel. Those connectors are identical and it is possible to switch them.

Disconnect the throttle cable from the throttle body and the cruse control cable. It is possible that a bound cable or incorrect installation is allowing the throttle plate to stay open.

Make sure you aligned the TPS with the slot when you installed it. The TPS is slotted, so there is an adjustment where you want the output voltage to be 0.45V and that is the middle wire (red/blk). You would need to back-probe the tps sensor connector and use a volt meter.

 

This is kinda what I've been wondering because if I turn the butterfly by the wheel, one of the cables comes off the wheel...

I'll check the wire colors and get a pic momentarily.

 

disconnected the cables going to the butterfly wheel. No change.

video link below. I plug the hole in the 10-11 o'clock area of the throttle body and the surge quits, but it almost kills the engine. plugging the hole at the 7-8 o'clock area makes no difference.
https://youtu.be/UBovwGf4Puk

 

If the camshaft timing is off 1 tooth, it really depends on which way it's off. One way it idles fine but won't rev. The other direction it revs fine but won't idle. Wish I could remember for sure which way is which, but I think if the cam is retarded it'll rev just fine.

 

Yeah the next steps are to put the intake tube back on, hit the intake with some carb cleaner and see if it's sucking air, if not, then we'll be tearing down to check the gears....

 

I'd probably double check the timing anyway. When I did the harmonic balancer replacement on my 99, I found that the lower gear had moved to the left 1 tooth. The rest of the marks lined up. That was all it took to keep it from running correctly.
It's a pain in the butt to dig in that deep, but for peace of mind it's worth the extra work.
I know I slept better after replacing the belts once I found the problem. In my case the PO thought it needed an engine.

 

When you mention the harmonic balancer that jogged my memory...

If you don't find anything, you can check whether the outer pulley has slipped against it's hub. The pulley is attached to it's hub through a layer of hard rubber, which can get oily or rot or shrink, allowing the outer part of the pulley to move a bit.

The actual timing sprocket on the crankshaft has a timing mark that you can check.

Another check is to remove the spark plugs & stick something down onto the piston. Rotate the engine around TDC and verify that the piston is actually coming to the uppermost position when the crankshaft timing mark is aligned. This is less accurate than the timing mark on the sprocket, but it's a lot easier to do.

 

I asked about this in an earlier post. Did you try this?

Make sure you aligned the TPS with the slot when you installed it. The TPS is slotted, so there is an adjustment where you want the output voltage to be 0.45V and that is the middle wire (red/blk). You would need to back-probe the tps sensor connector and use a volt meter.

 

I have not back probed this yet, but my brother (a genuine tech) aligned the tps when we installed it... but that is first on the list when I get to get back at it... (I forgot to mention it before putting the tube back on and spraying the manifold) It was aligned to where the old one was so I want to rule that out before tearing into the side of the motor...

luckily enough having had to tear into the side of the motor of the accord that got stolen multiple times, we're almost old hats at it now... lol I can tell my 15 and 17 year olds to go tear it down to the timing belt and 45 min later, they've got it done... They'll like this one better I'm sure as all the plastics on this one looks nice, the ones on the old one were chewed and crunchy...

 

Also, make sure G101 is attached (see pic). You may want to unbolt it and clean the eyelet and bolt with a wire brush or sand paper.

EDIT: It is on the driver's side of the upper intake manifold.