'96 Explorer Misfire Issues

[greatawakening]

1996 Explorer, 4.0L, V6

Okay. The story behind the origins of this issue...
In February, I had a cylinder 4 misfire so I changed the plug... No others, just that one. Still ran rough so I started driving a different car and mine sat in the driveway until a couple of weeks ago. Replaced the remaining spark plugs along with the wireset, still runs rough, still not driving it.

Checked the engine codes and P0304 came up, cylinder 4 misfire (still) along with P0174- System too lean (Bank 1).

Asked around a got many different responses... Bad fuel injectors, intake gasket and O2 sensor were the top three.

Any other opinions before I buckle down and take it in somewhere? Don't wanna have to spend money on something that might not even be the cause or something someone else just as knowledgeable can fix. Don't have that kind of money to play around with to begin with.

Any help is appreciated...

 

[alohamonte]

I had a p0304 code just a few days ago.

Here's what I did. I pulled the plug, which was heavily soiled with carbon. How did yours look? I used carb cleaner to spray into the cylinder head to clean it out. There was a lot of deposit in there.

Installed a fresh plug and it drive much better, code hasn't come back. I plan on pulling the rest and cleaning them out the same way.

 

[koda2000]

i would start with a compression test. if cylinder 4 is okay, then my guess would be a fuel injector issue. the lean code indicates unmetered air is getting into the intake on bank 1 (happens to be the side with cylinder #4). this may be part of the problem or just a coninscidence. the lean condition could be a vacuum leak or an intake manifold gasket.

 

[deweyville65]

96 4.0 V6 bank one is cylinders 1-2-3, right bank, am I wrong?

 

[koda2000]

96 4.0 V6 bank one is cylinders 1-2-3, right bank, am I wrong?

you're right... sorry, brain fart.

 

[greatawakening]

How do you go about doing a compression test?