Easy way to test it is swap it out for a working one ie if you know someone with the same sort of car just see if you can borrow theirs to see if it fixes the problem if you cant do that just follow the procedure for testing in the service manual. Ive heard a faulty o2 sensor can cause idle issues as well so might be an idea if you have ruled out everything else to check that out.

Your TPS should be 0.48 volts when your throttle plate is fully closed, id adjust it slightly.

Does the idle problem only happen while applying the brake by any chance?