I bought the car for a couple hundred bucks to have as a spare when/if my Santa Fe is in need of repair etc. because I drive for a living and can't afford down time.
The engine was running rough and we did a series of diagnostics on it and found the head gasket was gone. (There was a shock), so we replaced it and although it was running much better it was still very rough and would chug when taking off from a light etc.
We then pulled one injector at a time and tested them and sure enough one was just dripping fuel out and not spraying a fine mist.
We put them back in and tried to hunt down some injectors but everyone wanted too much money and the local junk yard was out of them.
So while I was placing an order for my daily driver for Amsoil oil I saw the Amsoil PI on the front side and ordered a couple bottles, one for my Santa Fe and 2 for the Neon.
I put the one in and ran it and by the time the engine got through that tank of fuel the engine starting running almost normal. I pulled the problematic injector and found it was spraying almost like the others. So I put it back in and ran a second tank with the PI stuff and the problem is now gone and hasn't returned.
Albeit this may not fix all injectors but if fixed mine and it's the only thing I will use for cleaning my fuel system because if it can dislodge dirt/debris from an injector that was virtually clogged then I'm sold on it.