Car wont idel and revs some times for no apparent reason its a hyundai xl 1995 duz it sound like the iac valve

i'd try a fuel addative to clear through fuel,cylinder/valves and the cat converter may have a carbon/sludge build up ,cheaper than getting iac and the idle may be the blockage symptom give it a go nothing to loose,must have quite a few miles on it

Whoa. Stop. Take the valve cover off. You'll probably see the problem. Maybe a rocker arm has come loose.

I doubt it is anything other than the iac valve or the computer.
You could unplug the iac and see what it does, the throttle cable could be hanging up in the car too.

I would say that is EXACTLY what it is! you've already "tested" it.
you could try cleaning it out. carb and choke cleaner works good

I would replace the IAC air bypass valve, also I would have the fuel injectors cleaning service done by a dealer, not the pour in the tank cleaner, it doesn't work.

clean the idle air control valve and pcv valve with spray carb cleaner. The IAC controls idle speed but gets gummed up. The pcv valve may cause a vacuum leak as well so clean or replace. And lastly clean the throttle bore and butterfly valve using an old toothbrush and some towels. Check the electrical connection at the IAC for security and corrosion and clean as needed.

it sounds like the idle air control valve is messed up test with a voltneter and replace

From your description, most likely there is a problem with the Idle Air Control (IAC) valve. Its job is to open at idle to let air in when the throttle is closed. Either it is clogged, or it has gone bad. You will need to remove it and clean it, or replace it. It is bolted to the rear of the intake manifold. When you remove it, try starting the engine with the valve removed so air can get in the intake. If the engine idles ok, you'll know that the IAC was causing the problem.

Another possibility is a leak in the vacuum system. With the engine running, listen closely for any tell-tale hissing sound. Inspect all the vacuum hoses and the air intake duct, and repair as needed.

Check for vacuum hose leaks or component clogs. You can use vacuum pressure tester.
or turn the idle screw down.

remove and clean the (IAC VALVE) thats the one on the throtle body