All I know is ive changed the plugs, wires....coils and Igniton module are fine..Took it to autozone had them run diagnostic's on it said cylinder 4 misfire and o2 senser heat was out.....could a simple o2 senser cause that much of a problem??? And I was reading the other thread and i'm gonna try switching the injector's and see if that fallows and is that something hard to do?? And it's not a problem at any certain rpm hot or cold you can tell a cylinder isn't running..any info help's...