Accelerator sticks - not slowing down?

The spring worked fine, I used cleaner to clean out throttle intake and throttle itself, there was a lot of buildup and it was causing idle to stick. My accelerator problem is fixed, thanks for your help!

When I put on gas car engins runs fast but car dosen't respont, need reduce fuel petal move car along slowly started friday.

Thanks! Will try the battery leads shorting step today after work. That is a really good idea, wish I thought of that! With the IAC valve, what part is brass? The plunger, the cup? Or better yet where on the IAC is the insert located?

After pulling and shorting battery cables there is better idle, less frequent hunting of rpm in Park and gear with brake applied and doesn't go so high as before when turning on the climate control, but the sticky accelerator issue is still there. Just not as pronounced. If I unplug the IAC the idle drops a little bit with no climate control on and in Park, and with it on it almost dies when the AC clutch kicks in every ten seconds or so. But when I drive down the road with it unplugged, the sticky throttle problem goes away entirely. I have checked the IAC and it is not a brass model, and the spare I purchased is a brass model and when I plug the brass one in, the rpm goes nuts, so I am guessing it is the one for the other engine? The original IAC was thrown out last year so the one I have been running on is supposedly the correct one? I noticed the brass one has a stamped Roman numeral I stamped inside the chamber and the one without the brass insert has a Roman numeral II. You mention there are two different valve designs? How can I tell which one is for this car? I am tempted to adust the idle manually and leave the IAC unplugged. Thanks so much for your help. Do you have any further suggestions/guidance?

Here is a side by side comparison after cleaning the one without the brass.

Car eventually slows down, but only after quite a while. I can travel miles at forty five mph without touching the gas. This is true if I use the cruise control or not. If I apply the brakes, it will slow down, but it is like the gas pedal is still being pressed down. When I place the transmission in neutral, the rpm's go up. This only happens when in gear. When I come to a stop, I have to brake until it shifts to first gear, then it settles down to a manageable rpm. It idles at 750 rpm's at a stop. But once I take my foot off the brake, rpm's will slowly climb up to 1,500 rpm's shifting into the next gears. I also noticed that while accelerating up to fifty five to sixty mph, there is sometimes a "rough" spot around forty five to fifty mph where the car sometimes loses power or shudders very briefly and feels like I ran out of gas or is trying to shift gears, but then just as quickly, it recovers. I also must add that whenever the climate control switch is placed in any position clockwise of the center off position (floor and dash, floor, WinDefr and floor, WinDefr, respectively), or in the two AC settings, the rpm's spike up to 1,500 rpm's and the AC clutch engages. This does not happen when using the dash vent position. I thought that the clutch should only engage when set to AC/MAX AC or the two defrost positions, but maybe that is how Ford does it. In any case, the spike in rpm cause the vehicle to suddenly lurch if in any forward or reverse gears. There are no codes being thrown by the computer.

Steve, where the heck were you last year when I started this mess! You have been incredibly helpful in my quest to fix this car. I have literally put over eighty man hours the last two weeks chasing this problem, not counting the time from last year, countless visits to the "parts" store, and mom and pop mechanic shops. I have the part on the way this time I am cutting my losses and ordering directly from the local Ford dealership. (Actually I am adding to my $$ losses, but saving myself further heartache and time visiting all the parts stores in search of this elusive part).

As far as the heater core flush/filter install goes, I will have to look into that. I would have to take it to a friend's garage (with heat and running water and a drain) to do that, I think I would do your method of just buying the parts instead of the "kit". This car seems to get that core plugged issue, something must be rotting away internally to plug it up so badly, so quickly after a flush (second time in two years). One possibility for the low heat issue could be a fresh air mixer/vent damper not closing/opening fully when in the max heat position (so i'm told by the guy who flushed the core last time). Do you know how to troubleshoot this so I can eliminate it from the possibility. I just had the thermostat replaced on last Friday (no effect), and the core flushed on Monday worked better-ish for a day, and then low heat issue came back a day later.

Thanks again, and I will post the results on the IAC later today.

The new OEM IAC works great! Just need back off the throttle stop screw a little bit (it's nearly flush now, as the deceleration is still a little too sluggish for my likes.

I did that when I installed the new IAC. I now do that every time I change a component. I read somewhere that the throttle stop screw should be set fully backed off and then given one full turn clockwise, mine is set at 2 or 3 full turns.

Everything is running just fine now. Time to give it back to my daughter. This was quite the learning experience! Thanks again, Steve!