Surging Idle after H/C/I change... Help!!!

Ok here it is, I just replaced the Heads with GT40P with 1.90 x 1.60 valves, TFS Stage 1 camshaft, Professional Products Typhoon Intake, 24lb injectors, 255LPH fuel pump, Adj. fuel regulator (Pressure set to 32PSI with the vacuum line off and jumps to about 37 with the vacuum line on), Autolite 764 plugs gaped at .45, FRPP 9mm plug wires, FRPP cap and rotor, TFI module and 1.6 roller rockers. I am running a 65mm Throttle body and the TPS is set to .98 volts. I am also running a C&L Mass Air Meter with the coreect 24lb sensor. Car runs will strong and has dynoed over 300 HP... The problem I am having is the Idle. Sometimes it is fine and idles at about 950 RPM then I put it gear and drops to,about 750-800 RPM and is fairly smoothy. Then sometimes it will idle at about 1100 RPM will kick up to about 1500 when put in gear. I can actually put it in gear and not touch the gas and it will idle at 1500 rpm and move the car down the road at 25 mph... I am at a loss... When it does idle right it runs smooth as silk and has a lot of power and throttle response. When it is not idleing right it is very sluggish with hesitation in the throttle.

Does anyone have any suggestions for me, this is driving me bannanas...

Test ya IAC check for vaccum leaks but do the right thing and run codes and start testing.... for anyone who doesn't like this answer you should have gone carbed!!!!

Test ya IAC check for vaccum leaks but do the right thing and run codes and start testing.... for anyone who doesn't like this answer you should have gone carbed!!!!

Covered, Replaced the IAC with a new one and did not find any vacuum leaks...

This is really annoying...

Covered, Replaced the IAC with a new one and did not find any vacuum leaks...

This is really annoying...

Something interesting... If I unplug the IAC it idles smooth as glass... So I purchased yet another new IAC and hooked it up, same problem... Idles fine unplugged and bad when plugged in... This has really got me stumped... I am almost tempted to leave it unplug except for the fact I still have a operating AC unit and need it.

You have to go farther down the line and test things that would cause the IAC to screw-up even when the IAC is good. I'll be honest this is what I use to deal with at work. I would have to crack open a book or use the Snap-on Vantage and find the next pinpoint test to run and depending on those results I would know what the problem was or where next to test.

It's almost impossible for me to give you a real good idea of where to goto next, when I have not worked on the car and gone through each thing methodically. On the net all I can do is point you to the common problem areas check those and if that doesn't work you need to invest in some books, equipment, or pay a garage who truly knows how to deal with modded Mustangs.

I have a dumb question? Have you gone and reset the computer to learn the cars new perimeters?

Some have had luck with "clocking" their MAF. Rotate it some and experiment. Some prefer Pro-M over C&L. Surging is so common after major mods. How's your TPS voltage? Make sure it's correctly set. There's also a throttle stop adjustment screw on your throttle body that you can adjust - CAREFULLY. After you do this, you do have to re-set your TPS voltage.

Are you throwing any codes??

LOL