I'm new to this forum. I just bought a 97 gt mustang. Really like it. My check engine light came on so I used a scan tool to check it out. The code came out p305, I think. Anyways, I did this at Schucks. The print out said my number 5 cylinder is misfiring. I tried changing the spark plug. I didn't help. Then I tried using a different plug wire to see if it was that. I was still the 5 cylinder. I also tried switching the coils around to see if the misfireing cylinder would change to another. It still was the number 5 cylinder. I was wondering if any of you can think of another reason why I have this misfire and how I could test more for its cause. Thanks for the help guys.

 

Sorry, I should've researched first. I did some looking but still don't think I've found anything. Could it be my fuel system? Is it a dirty fuel filter or a bad injector?

 

Could be either spark plug, coil, or injector. Sounds like you checked the first two. To see if the injector is firing, start the car up and let idle. The, take a long flat-head screw driver and place the tip on the top of the injector. Then, put your ear up to the handle. If it is running you will hear a repeated clicking sound.

Course, the missfire may not be constant, but only under certain loads.

 

Try moving the injector to another cylinder and see if the miss follows.If so,replace the injector.

 

Thanks guys. It was my injector. Replaced it with a new one and it runs great. Thanks for all the help.

 

One question before you go.How did you figure out what was wrong.The listen test or by moving the injector?Both ways work,but for different malfunctions.

 

Sorry for bringing back an old thread. I just feel bad for not responding back. I used to listen test to see if it was bad. What's the difference in the two tests? I tried switching the injectors and it didn't do anything. But I put in the new injector and the misfire stopped. What was it???

 

That sounds like an electrical gremlin.