hey um my cobra just started running like crap.it feels like an older car with water under the cap...it spits,sputters and stumbles...i just changed all 4 o2 sencors and all the plugs...passenger side back plug was almost flat,,all the others were weyt with gas...feels like the car is starving for something..i started to do a commpression test,front left side cyl. was 148 than the starter took a crap on the next try..im gonna try again today..what do i want to see with commpression test