01 4.0 powertrain in an 06

[macleanflood]

Correct. No I haven't changed them. Wouldn't they throw a ck eng light ?

Yes typically. But... sometimes folks remove the check engine light bulb. And you theoretically can adjust the tune to remove them from the PCM.

I don't know the history of your TJ...but we've seen all sorts of hackery from previous owners. It took me two years of work to undo a lot of crap on my Jeep... getting it to drive straight, not throw misfire codes, evap codes. Get decent fuel mileage. No exhaust leaks. List goes on, for me...

-Mac

 

[LJ owner]

Yes typically. But... sometimes folks remove the check engine light bulb. And you theoretically can adjust the tune to remove them from the PCM.

I don't know the history of your TJ...but we've seen all sorts of hackery from previous owners. It took me two years of work to undo a lot of crap on my Jeep... getting it to drive straight, not throw misfire codes, evap codes. Get decent fuel mileage. No exhaust leaks. List goes on, for me...

-Mac

Decent fuel mileage? My F250 Diesel gets better mileage than my LJ, LOL