to be honest i dunno what it is.
but you can put it iin your gas in your oil and induct it in your intake
and it cleans everything out pretty well.

a lot of people will recomend it if your not getting great mileage.

 

The 4.0 is hard to beat with the stock champion coppers. A lot of people have tried things like NGK and Bosch platinums and have not gotten good results.

I am getting an MSD cap and rotor soon but I think I'm getting a snorkel first.

Ill check to see what the prices are, I'm a mechanic too lol.


As for o2 sensors, Bosch makes a good product with a cheap price. They go for around $35-$40 a piece.

I'm replacing mine with those and adding potentiometers to them. The potentiometers will allow me to manually adjust the signal sent to the PCM to change the air to fuel mix. My XJ runs a little rich so this should help me out.

As far as headers go, the stock exhaust manifold on the XJ is pretty free flowing. I'd just get another one of them unless you see headers for a lower price.

Another thing to try and save gas is the Transmission control module mod. You add a couple buttons to interrupt circuits so you are able to trick it into shifting on command. Its nice to be able to keep the rpms low

 

how would you do that transmision mod

 

There are two wires leading to the TCM. You add switches to each of the wires to interrupt the circuts. As soon as the circut is interrupted, the TCM switches from normal operation to manual shift.

Google it, there a couple of writeups with wiring diagrams out there.

 

full tune up
exhaust leak #6 pipe
2" lift
stock tires
stock Jeep
18.5mpg
not too bad considering...

3.5" lift
31x10.5
exhaust leak still
stock 3.07 gears
i use it for work - carry aout 800lbs worth of extra weight - including metal gas tank skid and swing arm tire carrier with tire
about 17mpg

i went 8000 miles and dropped to like 15mpg - gave it a oil change and it went up about 1.5 mpg

im getting 703 injectors soon, hoping i will get at least 1-2 out of that to put me back to original
im hoping getting new pipe to fix my leak and a snorkel/cowl hood will put me over the top

 

Mine had a loud whistle because the belt was too loose. it didn't feel loose, but it was. The belt route is crazy so it needs to be super tight.