Possibly a bad TPS, but several other things need to be checked/tested also.
You can't do it yourself so get it somewhere before you run it again.
If you slam it into gear at 1300RPM you'll be having gearcase problems that are way more costly than the elevated idle.
I had one in yesterday that had a rodent nest under the cowling, jacking up the linkage. Guess you could check for that yourself.