My cylinder 6 misfire was caused by oil from the valve cover gasket leaking into the spark plug well. Had valve cover gaskets replaced and other than the Three/Four Amigos; its been problem free.

 

I don't know if the heads have been replaced, not since we have had it. I will mention the valve cover gaskets to him. I finally got the list of fault codes from my husband, this is what he gave me.

P1590
P1884
P0444
P1551
P1514
P0102
and he said random misfires on all cylinders, P0300-P0308.

He is thinking of trying the MAF sensor next, any suggestions?