ok first question is.... how big is the 90 v6 gas tank
.... im barely gettin about 175 or 180 miles to a tank is this decent?
.... is the stp gas treatment really worth it?

 

15.5 gallons

 

here is a question
when you put gas in how many gallons are you putting in?
if you have a 20 gallon tank but only put in 5 gallons how large the tank is means nothing

 

Steady state highway cruising should be about 26 MPG. Around town can range from 18 to 21 MPG (maybe less if a lot of stop and go with a heavy right foot).

RBob.

 

also, hes in Cali, they put crap in the gas to make it more "ozone safe", but it kills your MPG. Kinda a trade-off.

I belive thats all Dean gets out of his v6.

 

i dont knwo the size of the tank because ive been sitting on empty before and put in 14 gallons wen ive topped up and sumtimes lower. so i wanted to clear it up. i think they like to mess with the meters here so they can screw us over on gas. but i guess it seems to be ok.

but now is the stp gas treatment worth the money?

 

you would probably do better having a professional do a fuel injection cleaning service (GM top engine clean does a grat job of cleaning dirty injectors) . that is of course if that is your problem. what is the condition of the engine, compression test readings last major tune up, fuel pump condition, timing chain slop? these engines can get heavy carbon build up on top of the intake valves causing mpg losses. does the O2 sensor react slow? finally is there anything pluging up the exhaust?

 

i get 20 mpg beating it where ever i go. 24 mpg around town if i am a little easier on it and it has 193,000 hard miles on it.

 

mid 30's for me...hit 39 once also....hmmm, that or i'm going crazy. Had to test the damn thing more than 40 times, and still re-compute it now just because i'm so amazed at it. Average has been 33, with a range of 29-33 on highway everyday.

On the contrary, my in town SUX!!! well, not really bad, but only average.

Changes made,
New PU coil
New Coil
New Cap
New Rotor
New Wires
New Plugs
Cleaned K&N
Flowmaster Muffler
Timing set correctly and bumped to 12* (after shop screwed it up and set it at 0* advance)
And the topper.
Finally fixed my TCC selenoid, have a manual locking switch which i engage once i'm cruising on the highways, that's the real helper, and will hopefully add some time to my transmission. Didn't have it working for several years, never noticed it, was still getting 22-25 mpg on the highway, not great, but ok. With the switch going, i could drive forever.....honeslty, depending on how flat the road is, i could probably pull 470 + miles on a tank.