So it started out with a p0304 and right bank lean code. After doing a little reading I came to the assumption that it was cops and plugs. So I avoided doing the job for 2 years because I was afraid after what I had read...2 years later it got bad enough I had to fix it.
So without doing any diagnosis at all I swapped out the plugs and cops, using motorcraft of course. Didn't use liquid wrench or anything, just light pressure and a combination of extensions und universals. Everything went as smoothly. It was obvious that the right bank was running super lean, wish I had done it sooner..
After getting it back together it ran smoother with no codes appearing, but still had a slight miss that was hard to notice. Couldn't figure it out so I went to basic thinking..
What does an engine need to run?
Air, fuel, compression, ignition.
I had fuel and ignition for sure so I ran compression and got some funky results. Moved to leak down and everything showed fine. Found out I was doing compression tests wrong, redid it and all was good.
At this point all that was left was the air factor. So I went to the shop at the college and ran smoke through the vacuum lines. There was the problem... Smoke poured from brake booster, EGR, lower intake, and valve cover on left side. Spent about 120 bucks fixed all this, which was relatively easy no special tools required, except Ford fuel line tool. (which I made from a sharpie lid) the result was 18ish MPG around town 25ish on freeway after 200 miles.
Imagine how much time, energy, and money I could have wasted with properly diagnosing the issue..
Moral of the story:
Stop throwing parts at an issue until you know what it really is.
I was ready to pull and rebuild or replace the motor.. Or drive it off a cliff... That sure wouldn't have been cost effective.
