Rough idle and white spark plug

[1989dangeroustoy]

Trying to get all the bugs out of my recently aquired 96 4.0 . Here's a little history, it has a valve tick and I just added some mmo to the crank case, I cleaned the maf and icv and just changed the spark plugs yesterday, it still has a minor rough idle and the number 1 spark plug was white and the rest were the normal tan wyith. No misfire codes , no tailpipe smoke

 

[1989dangeroustoy]

Any takers? I'm guessing itsi an intake leak or clogged injector, any other suggestions

 

[Dono]

How did you make out? I think your diagnosis is spot on. Always a good thing to do a compression test, or leak down if you can