07 Ford Ranger P0304 keeps coming back on!

[Purrfect312]

I have a 2007 Ford Ranger and about 6 months to a year the check engine light came on and it displayed PO304 which from the research I did, means that cylinder 4 is misfiring. I went through all the possibilities and did the following:
-Replaced all spark plugs
-Fixed all air leaks that could find, used brake cleaner to see if any revving happened when I sprayed it
-Changed out all coil pack wiring
- replaced camshaft sensor
-replaced crankshaft sensor
- replaced coil pack
-Replaced fuel injector
I also have my RPM needle jumping when the car is in idle. I need help! Any suggestions?

 

[RonD]

Welcome to TRS

In 2007 Rangers there were 3 engine options
2.3l 4cyl
3.0l V6
4.0l V6

Which one do you have?

And do you FEEL a mis-fire when driving?

 

[Dirtman]

Well it's in the 3.0 forum so I'm guessing it's a 3.0.

Don't the 3.0s have issues with the valve seats of that era that can cause misfires?

 

[Purrfect312]

Welcome to TRS

In 2007 Rangers there were 3 engine options
2.3l 4cyl
3.0l V6
4.0l V6

Which one do you have?

And do you FEEL a mis-fire when driving?

I have a 3.0 abd it drives rough

 

[RonD]

Its possible, if its a 3.0l, the recessed exhaust valve seat TSB was for 2004-2006 3.0l Rangers but early 2007 could fall into that range
And it could present as a single misfire at first, but usually this showed P0316(random misfires) and multiple P030X codes

A compression test should show if #4 has slightly lower compression than other cylinders