Misfiring in the no 3 cylinder

[Josh40601]

Hey everyone, as you all can see, I am new to this forum, but i am not new to forums in general. This is my 2nd mustang and it is a pile right now, but i plan on giving this car a second chance. The issue I am having is just as the subject line states, the number 3 cylinder is misfiring. The car is an 89 5.0 LX Hatchback. If anyone knows what the heck could be causing this, please for the love of Jesus tell me!! Any help with this matter would be greatly appreciated

 

[Mustangcwo]

If it is only misfiring on one cylinder and it stays consistant "on that one cylinder" it can only be the spark plug, spark plug wire or distributor cap. Now, that is if it is a "misfire". That means the spark plug is not firing on that cylinder.

If the spark plug is firing on that cylinder, then you need to conduct a compression test to verify the cylinder is sealing. This could be bad compression rings or a valve train problem i.e. broken spring, loose rocker (ticking sound), rocker fell off, bent valve.

First you need to pull the plug and verify spark. If you have spark, then you need to conduct a compression test.

 

[Josh40601]

That makes life sooo much easier. The shop that told us it was misfiring rebuilt the topend so that leaves me with one of 3 problems. Going to replace all the plugs and wires and cap Friday. I'll let you guys and gals know if that fixed it. Thanks a lot for the quick response and the help. Maybe i will get this car finished a lot sooner than i thought....