Been having this misfire for quite awhile now, I cannot for the life of me figure out what’s causing it. I’ve replaced the MAF sensor, fuel filter, cam and crank sensor, tested the fuel injectors and they’re fine, fuel pressure is good, also replaced plugs, plug wires, and ignition coil. If anyone has any other ideas of what could be causing this misfire, please let me know.

 

Welcome to the forum

What YEAR Ranger?

Any cylinder needs 3 things to fire
Spark, at the right time
Fuel, in the right mix with air
Compression, above 120psi

If you have a misfire then you are missing one or more of these 3 things

Compression should always be the first test because its black or white, good or bad, spark and fuel can be intermittent

So thats what you should do
Test at least 3 cylinders compression levels
3.0l is expected to be 160psi

It is way better to pull all 6 spark plugs and test compression on all 6 cylinders at the same time, but up to you

If you don't test compression first then you get what you have now, $10, $50, $20 here and there trying to fix a misfire, which is fine, its your money and time, but if it is a compression issue then it was a waste of time and some money, new spark plugs are always money well spent

 

It’s a 2000 ford ranger

 

Could be a burnt exhaust valve in #6

Test compression, a kit is $30-$50, but they can be rented as well

Needs to have multiple threaded ends, flexible hose and a release valve

 

If cylinder 6 is lacking in pressure would it be the exhaust valve or something else?

 

Most likely reason for a cylinder to drop more than 20% below its expected compression is almost always exhaust valve problem

Rings and intake valve is far less likely

You can put a cylinder at TDC then put compressed air into its spark plug hole and listen at the tail pipe, you will easily hear air coming out unsealed exhaust valve