Symptons of a bad coil pack and fuel injector

[chuck ray]

Had a po 303 replaced the plugs and wires put in the gas tank two bottles of berryman b12.idles smooth but still a miss sometimes shifting thru the gears also a small backfire when you race up the engine quickly. 1999 mazda b2500 2.5 l engine 137k.can you test the coil pack and how.

 

[swynx]

i dont know that you can test it. if its the original its about time to replace it any ways. a lot of people never replace the coil pack, my 4.0 had the original one from 300k miles ago on it. i replaced it and it drove like a whole new truck.

pull the spark plugs and check them, maybe one of them looks different that the others. thats your problem cylinder.

i know they make a tool that you put on the coil wire so you can see if it is sparking. but i dont know that that would help you much. i would check the plugs and if theres an odd ball check the spark plug decoder images in the back of a haynes manual to see what your problem is.

but id just order a new distributor/coil from rock auto, it couldnt hurt.