Hey guys, My 99 3L is getting up there in miles. I would like to do some maintenance, as i feel its lacking in power and gas mileage. I got 17.5 mpg on a 400 mile highway trip. I think I should be getting in the low to mid 20's on the highway. About my truck: Gibson cat back, 31.8 inch tires. Changed rear end fluid and air filter/fuel filter. What should I replace at 135,000 miles? As far as I know nothing else has been changed. What else will give me a bit better gas mileage?

 

What year did the cam syncro's start going bad ? I'd keep an eye on it.

 

How about plugs and wires?

 

check the air in your tires.

 

Plugs, wires, fuel filter, air pressure, new shocks, new bearings, and maybe a couple fills of premium. My boss told me that because it burns cleaner it helps break up crap. Also, maybe fuel additives?

 

bearings for what?

 

didnt really think about that, good call

 

For a 95 ranger with a 3.0 what should it idle at RPM wise? For some reason mine is idleing at 1250. But ya, what already was mention. Plugs, wires, fan belt, clean all the sensors you can.

 

guess i need to do plugs and wires then lol.

 

And your boss is wrong.Premium (higher octane) fuel is meant for high compression engines to stop pre detonation.
In a lower compression engine like the 3.0 it's possible that not all of the fuel in the combustion chamber will burn off , which can reek havoc with the cats as well as leave deposits behind.
Run some Seafoam through it instead.

 

Thanks for the heads up!

 

Front wheel bearings.

 

Ha ! reread the OP you're running bigger than stock tires. Did you compensate for the difference in tire diameter when figuring your mileage ?

 

I got some real benefits from doing my cat at 125k. I mean WOW!! benefit. You may not. If it is not a problem, then a change won't fix it.

If not done yet then I would do:
Plugs and wires
Seafoam
Fuel Filter
air filter
Xmission fluid
Xfer case fluid if applicable
Catalytic Converter Cleaner from JC Whitney (optional but I liked it)
Others may balk but I got benefit from the Gumout injector cleaning at Walmart.
MAF sensor cleaning
PCV valve
Front diff if applicable
Serpentine belt
New shocks are nice for a while
Oil and Lube
Pressure wash under the hood. (Tire cleaner works nice on the grease. Save enough quarters to rinse it off.)


My 95 3.0 idles at about 1000 RPMs at normal operating temperature.