h1gh0ctane

Okay, seen some similar problems on here. This lumina gets hot, then dies, won't restart for at least 15 minutes. Check engine light comes on, and it cranks, but no start. There's no codes on here, it just flashes 12 over and over. I took it to a guy and he "thinks" its fuel injectors. However, I cannot pay him upwards of 600-800 dollars to MAYBE fix my 1000 dollar car, right? Also, it has a bit of a hesitation when driving cold, especially when you brake, or come to a stop, it ALMOST dies. So, first question, if the injectors are bad, why does it run cold just fine? Second question, would a really good fuel injector cleaner help out? And third question, how much of a pain is it to change the injectors? If someone could give me an idea of what's involved, I may just buy them and swap them out. Any help would be great, thanks.

Also, the guy I took it to said that two injectors were easy to get to so he tested them. One failed when the car was hot, but passed when the car was cold. But another guy I really trust I called in another state says that an OHM test on an injector is BS........any thoughts??