Engine light came on, said a cylinder 3 mis-fire.. Replaced all the plugs, reset the codes and drove it through it's drive cycle and then got a random mis-fire code. Did the drive again and got a cylinder 3 and cylinder 6 misfire. Then I replaced all the coils with the yellow accel's, everything seemed great, then that damn light came back on throwing a cylinder 3 mis-fire again. Before I start pulling injectors, it seems like Im not the only one that has had a similar issue....does anyone have a fix for me? Car is '00 Gt convertible

 

Miss fire is not necesarilly a lack of spark, or ignition related. It could be a faulty injector, or you could have a leak in the intake at that cylinder.

 

All cylinders compression test just fine so I am looking at injectors next. Car has 156k miles and they are clearly the original factory injectors. Thinking I should grab a set of the ford racing EV6 24lbs but just wanted to see if there are some computer issues that are known before I drop another $200 in parts

 

Why not swap injector 1 and 3 and then check the results?

 

That's the next thing I'm going to do but wanted to check if this is a common problem

 

It's neither common nor uncommon, if ya know what I mean. Faulty (dirty or malfunctioning) injectors aren't really ever at the top of anybody's list of things to check/replace when diagnosing a cylinder specific misfire, but since you have already replaced ignition components and we can rule that out then I guess that the injector is next on the list.

Keep in mind that if you install 24# squirters you will absolutely need a tune. If on a budget, I have heard good things about an online injector cleaning/reconditioning service called injectorrx.com.

 

Hey guys- finally cleared the mis-fire and wanted to share. After replacing all plugs and coils and still getting a #3 misfire, I pulled the #3 fuel injector expecting it to look terrible and it was surprisingly clean; almost new looking. Went ahead and swapped it with the #1 injector, test drove, sure enough still a #3 misfire. I figured at this point it was computer related to I grabbed my Bama tuner I had been waiting to use until this was done and loaded the street tune based off all my current bolt ons......probably should have done that from the start. Immediately solved the problem and smoothed out the engine through the entire power band. Passed smog this morning no problem; I should add too that I have a bassani x pipe with high flow cats and had no trouble with smog. So glad this is fixed!

 

That makes almost zero sense that the stock programming would be responsible for a cylinder specific misfire, but if it's running good now then I guess that's all that matters.

Where in CA are you?

 

To me it appears the issue was that the computer needed to be reflashed and the only thing I had was the bama tuner. My plan was to load a program so I could then re-flash it back to stock but once it started running right I stopped. And I'm in Santa Ynez; central coast of CA

 

I should also mention I was chatting with a local shop today and he said they see computers needing to be reflashed all the time on older cars. Not necessarily Fords per say, but the point he was explaining was that it was not uncommon for a 16 year old car to need a computer reflash