Okay so I have a cylinder one misfire her and I think I just about done everything to try and fix it but it still misfires the idol runs rough I've changed out all sparked plugs, crankshaft position sensor, the ignition coil pack and the fuel injectors twice! Idk what else to do and any help will be appriciated, its starting to eat my gas!

 

Depending on the year, which you didn't offer up, it could be a bad valve spring and/or carbon build-up.

 

A compression check would be a good place to start vs throwing parts that aren't bad at it.

 

Yes.

 

Any codes? What condition (color) is the spark plug from cyl 1?

 

Sorry it is a 2001 sport edition 4.0L. The plugs have slight carbon build up but i replaced them about 3 months ago.

 

Carbon already after 3 months?? Yikes!

Comparing to this chart, definitely carbon and not oil eh?

 

I will take the plug out again and post a picture for you!

 

As cruiser said valve spring or carbon build up. Do a compression test. It should come back with low compression. My 01 had this issue. Head went to the machine shop and the problem went away and never came back.

 

I'd add that if you do decide to pull the head, try a replacement head because the factory 0331 heads are notorious for cracking. The cost difference between a new head and taking yours to the machine shop are negligible.

 

Can also be bad injector or injector connector, in addition to the previously mentioned bad valve spring or carbon buildup.

Pour/spray 1/2 can Seafoam down the intake. Next day pour/spray 2-3 cups of water down the intake. Have the engine fast idling about 2000rpm while doing this. Slowly over 5-10 minutes. Will make the engine speed slow if too fast.

Other 1/2 can Seafoam in 1 tankful of fuel then Chevron in the next tankful.

 

I agree with everything in the above post except skip the Seafoam.

I have a special "de-carbonization tool" that I use.