I recently bought a 1999 35th Anniversary V6 Mustang for my step-son for his 17th birthday. It's in great shape considering it has 183,000 miles on it. But it's starting to have a problem. It has a vibration and stuttering that I don't notice at highway speeds but it's very noticable when just cruising around town. I just put new plugs and wires in car when we bought it since they had never been changed, it still had the factory original in the car.... the problem seemed to get better but not completely fixed. After about a week of driving the stuttering came back along with the check engine light. I took it to the shop and it's showing a misfire on cylinder one. They pulled the plug and it was cracked. They replaced the plug free of charge and it again seemed to get better but still not completely gone. Now after about a week I'm back to having the same problem again.... Anybody have any ideas? What could be causing this over and over again? And why is the problem never completely going away?

 

Any other codes ?
Is it still the spark plug going bad everytime ?

 

it was throwing a cylinder 1 misfire code is what they have told me.... I haven't taken it back to the shop yet this time and I haven't pulled the plug yet but it's acting exactly the same way this time that it did last time. The check engine light isn't on this time but I'm sure it will be soon.

 

yeah sometimes takes awhile. Im just curious as to if its giving any lean/rich codes as well.
Someone might leave that comment out say its just cause the missfire, but could be causing the failed plug if there is.

 

what kind of spark plugs you using anyways ?

 

Just regular Motorcraft Platnium Plugs

 

I've also ran a couple bottles of Lucas Injector cleaner through it think that might help, but that hasn't done anything either

 

Couple of things here, im not entirely sure what could be causing this. Just got some etra detail out of you that would help others who might.
You've done exactly what I would have said in the first place. So from here idk for sure.

Also, not to hate, but I suggest you join other forums. This V6 section seems very slow IMO.
http://www.moddedmustangs.com/forums/v6-mustangs/
Usually very busy

goodish:
http://www.allfordmustangs.com/forums/v6-tech/

 

Thanks!