02 4.2L E250 missfire problem

[TeamOK]

This van has two re-occuring codes (Po301/po316)with a check engine light I've erased with my code reader several times. The no.#1 plug & wire have been replaced, and a fuel fliter.It lacks the normal power it use to have in acceleration.There is also a exhaust leak, just before the catylatic converter.A fuel cleaner additive was used that did help earlier.

[72mino]

When you changed the plug and wire, was the plug wet? Your injector could be clogged enough to cause a miss. I don't know how easy it is to get to the injectors on your engine, but you could switch that injector with another and see if the code follows it.

Dustin