[01VBmustang]

I have had a slight hesitation/misfire under 2500 rpms every now and again for a couple months.

2 months ago i changed my plugs/wires, #6 cylinder was, by far, the most gummed up.

I installed an intake spacer yesterday. All the intake ports were gummed up except the one on the drivers side closest to the firewall (#6 i believe), which looked brand new.

What could be the cause of this? Is it likely that this is part of my hesitation/misfire problem?

 

[01VBmustang]

Bump...i also used seafoam a couple weaks ago.. maybe thats why only that one port is clean?

 

[Zatrekaz]

So #6 was gummed up bad when you changed your plugs, but #6 intake port was almost new looking when you installed a spacer? Something sounds off....

I am not very versed on this kind of topic. My only recomendation would be to take to a shop and have them look everything over really good. If it is a problem with one of your cyl then find out soon before it causes dmg to your pistons, valve springs, or worse... your whole engine.

Maybe someone who knows a bit more will chime in later tonight or tomorrow morning for you.