Poor mileage in 98 Silverado, 350 Vortec

[chevytrucks92]

Chevy SS, you may also want to raise your air pressure a little. This would help your gas mileage and improve your tire wear.

I dont know what the factory specs for air pressure are for you tires, but I would try around 44 or so psi. Now its not going to raise your gas mileage from 13 back to 18, but it would help a little.

[J-Ri]

Originally Posted by Silverado Brethern

I dont know how to figure exactly my highway mpg, but i have a 26 gallon tank on my '97 and i usually average around 8-9mpg. Figured by my 26 gallon tank gettin me around 200-250 miles. so i would be quite envious of someone who got near 15mpg. But i wanted the power of a V8 and i got it, so im not gonna bitch about the littlest thing like gas.

To figure mpg, take the miles since last fill-up and divide by the gallons the gas pump says you put in. I don't see how you could possibly be in the 8-9 range. I have a quadrajet carb (that is terribly out of tune, black smoke comes out the exhaust under heavy acceleration) on my 350 (3 spd trans w/o overdrive) and 4x4. I also have oversize tires with fairly agressive tread. I get 10 mpg letting it warm up till the temp guage starts to move (have to for it to even run in the cold), and keeping it running for 10-30 minutes for the heater after I get to school/work early.

[Chevy-SS]

Many thanks to everyone, especially Yukon and Thunder. I will probably just order two sensors tomorrow from gmpartsdirect.com, but I'll make a couple of calls around tomorrow just to check local prices. I gotta feeling the local prices will be higher, but ya never know.