Ok
I have changed the sparks plugs
The wires
New Air filter
New tires, and full to spec
Injector cleaner
Idle and timing checked and adjusted

And i am still getting bad gas mileage, i dont know what it is and need some help, i know it is a suv and wont get the best but i do know i should be getting better, plus i checked all my vacum lines, got them all hooked up and no leaks but i am riding rough around 30 to 50 mph, like a lag and kinda catch up feel..
any hints? i am spent thinking about it, i cant figure this thing out

1992 v6 3.0L

 

Replace your fuel filter that should help alot it sounds like when your on the gas its trying to push alot of fuel and its cloging the filter and causing it to spit and sputter? if that makes scense it sounded good to me? lol

 

You can't look for vacuum leaks - you've got to use propane or start spraying things down to catch them.

The other big influence on mileage is the 02 sensor... .

 

-check for codes the computer may be logging...search this site on how to jumper the diag port under the hood to extract codes and determine what they imply.

-Got oversize tires?

-Fuel filter sounds like a good idea

-Timing?

-Low compression?

-Check vacuum at hot idle...18-20, steady, is good

-Clogged Cat Converter?

-Old Oxygen Sensor...when they start to go, so does your mileage

Report to us your findings....

 

I had similar problems after having the distributor go out, and had it replaced by a Toyota dealership. Seemed like I got less power and mileage after thay did it. After trouble shooting we discovered the timeing was way off. As a result of the timeing being way off, now I have two bent and burned exhaust valves. Of course the dealership won't stand behind their work.

After my experience, I would check the timeing, and the compression. Rule out the big stuff, and the stuff that can cause more damage.

 

What mileage are you getting ?

What you consider "bad" and what is "normal" may be the same thing





Fred

 

don't know about if the fuel filter would really help. i had mine replaced with last month along with the clutch. i couldn't see any differences on the MPG. by the way, the new FF is OEM straight out of the sdealership. see my sig for my rig. still runs about 15.5mpg half hwy half local.

 

you should try replacing your o2 sensor

 

check your cold start injector, it might be bad and flooding the engine. also mess with your air to fuel ratio. get in there with propane and check vacuum leaks, all that.