improving gas mileage on surburban 98

Consider your self lucky your getting that good of mileage. Thats good mpg inho.

my 92 blazer with the 350 gets 16 on a good day. and Its half the size of your suburban.

Our 99 Jimmy gets 15-16 on the highway if were lucky and all we got is the

buy a different car. That's pretty damn good mileage for what you have there.

DRLs might cost you .0001 MPG. That's the least of your trouble!

Per hardworking:

On a good trip, I get 14.7 highway.

Once I got 16....

Yes lucky indeed, do not touch a thing except maybe tire pressure. I have a 89 4x4 burb that will do about 19 mpg at 65 mpg on a trip from Ohio to South Carolina on one tank of fuel (565 miles on 30 gallons of gas and it holds 40 and A/C was on too) Never checked it on long a pure flat land test in recent times. It has stock sized smooth tires with 3.73 gears, a large single exhaust with a flow master (3 inch exhaust and it is quiet in car) and it has 175k miles on it too. I also use premium fuel in it year round (occaisionally 89 in winter but it is rarely drive in winter) and the timing is set 8 BTDC as the baseline. It never ran as well or delivered much over 15 MPG when it ran on 87. Runs like a champ in current setup. I have had it since new and plan to keep it at least till kids are done with college in another 6 or 7 years.

Just an FYI - thats about the same I get on my Avalanche. No one ever believes me.

Try a couple tanks of higher octane gas and you may be surprised.

Something is wrong with that 99 then. My old 94 with 4.3 gets 18 around town and closer to 21 on the highway. The 2002 we just picked up got

Your getting great mpg! Try getting 12 city and 14 highway.