Little history, i bought a stock 97 spyder gst 2 months ago and the guy (mechanic buying/selling cars) said the car is perfect and he only had to "replace" one injector. 3 days after the purchase, car started loosing power. Few days later, it started shaking, misfiring and was running on 3 cyl. Took it back to him and he "cleaned" the injector. Worked fine for a few days and it started going bad and misfirinig worst again. I ordered a new injector and installed it, car still was not going 100% power but i was happy its running "OK" After a few days, total loss of power and stalling with ac on. A DIFFERENT injector went bad this time. Took it to a dsm pro mechanic and he found out ALL rubber on other injectors was bad so he replaced ALL injectors and put a new rubber on. Car ran perfect after 3k rpm but was dragging to get to 2.5/3k rpm. I never paid attention to mpg before but now i can see that its doing worst than my 5.4L Town Car

4-5 days later, without slowly decreasing power and slowly going bad, it started misfiring as soon as i touched gas pedal, shaking badly and i barely made it to mechanic. He said "burned up Injectors -The cause is currently unknown that's for sure."

Has anyone had any similar problems or does anyone have any clue why are they going bad. Any help is much appreciated. Thanks guys.