95 Sunfire throttle sticking ....

My son has a 95 Sunfire 2.2l. We bought this used as his first car "beater", but he likes the car (and the lack of a car note) and wants to drive it for a while longer.

We recently replaced the automatic tranny shifter cable due to the coupler at the trans end coming apart. I only mention this because the throttle issue showed up right after we completed this repair, even though the 2 really appear to be unrelated.

Any way, right after we got the console and interior back together, he took it for a test spin. He didn't even get out of the neighborhood before he called and said that the throttle had stuck on him. I drove over to where he had pulled over, checked the pedal movement, and it seemed fine, checked the drum on the throttle body (where the cable connects), and the throttle body looked like it was in the idle position, so I started the car, and it was idling normally. He took off again, and called a few minutes later to say that it had stuck again

Well, he got it unstuck, brought it home, and I pulled the carpet back again under the driver's feet area to see if anything was binding at the pedal end, and could find absolutely nothing wrong ... no binds on the pedal or the cable. So I got in the car, and drove it for over 25 miles all over town, dogging the snot out of it every time I came to a stop, and I could not get it to do anything wrong. I figured maybe some carpet backing or something may have gotten inside the cable housing when we pulled it back to replace the shifter cable, and we had finally cleared it, so I let him start driving it again.

He had zero problems with it for about 3 weeks, and then a couple days ago, it stuck again, only this time he was in traffic, and he couldn't get it stopped before getting into the rear of the car in front of him (no damage, and no one was hurt, luckily), but I can't let him take this thing back out without a definitive fix. I removed the throttle cable completely yesterday (new one is on order and should be here today or Monday), but I can not feel any binds whatsoever. The pedal assembly does not bind at all, the spring at the throttle body is still plenty strong enough to return to idle, and even overcome a minor bind. There is nothing coming in contact with the cable housing anywhere, either in the car or under the hood. Yet he claims that when it does stick, the pedal has not returned to it's normal rest position, pointing to something somewhere binding.

I am at a loss now.

Has anyone else experienced this type of problem, or does anyone have any ideas what else to check?

Any advice would be greatly appreciated.

Are the engine mounts in good condition? If the engine torques in its mounts under heavy acceleration that twist may impart some pull and/or binding in the throttle cable.

As you reported, you drove the car "dogging the snot out of it" but is the other driver operating it a little more spirited? That may make a difference.