Why guess or just swap parts?

Do the "one at a time pull off a plug wire to see WHICH cylinder is misfiring!" Then look at the plug.
If you find 2 that give very little change try switching them - probably crossed.

We can check firing order many times - always it seems correct - because we make the same mistake over and over. Have someone else check it tool

Only use the plugs called out on your underhood sticker. NGK's were used in some, but not all years and models.

 

this is the correct firing order and dist cap screw location...

 

Soybean, #1 Really is at 5:00, viewed from the side. (Right where there is a "4" in both diagrams.)(see post #3). Again, clockwise from there 153624.
And yea, the screws point just left of center of the front of the valve cover, that shouldn't have changed.

Yea, a good trick, it's called a "dynamic compression" test. With it running you pull one wire at a time off the cap. If nothing happens, (rpm doesn't drop), of course that one wasn't firing right. Even though you do that off the cap so you are not holding a hot wire, you will still probably get zapped. You can loosen them first with it off, helps that. Still I get it almost every time!

 

I just pulled one of the NGK's i put in yesterday and it is covered in black. Why is it fouled if I just put it in yesterday?

 

Is it sooty, dry? Then it's too rich. If it's wet, oily it might be just not firing.

We sort of jumped in with both feet here. How was it running when you bought it? Idling smooth with no smoke or unusual smells. Or idling rough, with black...or white smoke?

 

I pulled all the plugs and they are covered in dry black stuff but it looks like there's oil on the threads.

 

When I bought the jeep it had almost no oil in it. It idled smooth and drove fine. I put oil in it, changed the plugs and wires. I put the plugs in yesterday and they are fouled.

 

It ain't the NGKs. I run them in my 3 old Renix Jeeps with no issues.
The plugs that give problems are SplitFires, Bosch Platinums etc.

 

How's the line from your throttle body to the MAP sensor?

 

Its good

 

Maybe it's pre 96, and you bumped the tube from the inside of the throttle body that runs back to the MAP sensor up there on the firewall. That might explain it.

Edit OH! I see you added, it's an 87..., Yea, that MAP tube is crucial...

 

Thanks, I'll go check that now.

 

So there are two lines running from my throttle body. One is missing and the other was connected to my airbox? But the little plastic tube inside the rubber tube is broken off.

 

I dont even know. This is pissing me off. It ran fine then I put oil plugs and wires and it fouls the plugs wont idle right.

 

Hey dude, that's it! When Pete showed up I went to the store.....

At that rubber plug in the throttle body, it's the bottom one. It's often the tiny things that are a real b***h. The MAP up there on the firewall needs GOOD vacuum from the intake. You can tap anywhere but I repaired that tube. If you have enough sticking out you can fit vacuum line on the stub. Because it's vacuum (not pressure), a nice snug fit will do. If you need to get the broken piece out of there, it can be done with a little screw. I happened to have an actual extractor with reverse thread, but of course here it doesn't matter, anything that you could screw into the tube to get hold of it will work to pull out the broken piece. You can take another piece of that little tube too the store if you need, to size the new line and get a screw. Also you can heat and bend that tubing if you want to "go there.

If you tap to another vac line, you need to plug that hole. In any case the MAP is "KING" with the mixture. It tells the ECU how much you have your foot in it based on the vacuum it senses. If your line is broken, that would explane the black plugs.....(ECU thinks you have it floor-boarded!)