02 Avalanche 5.3 mileage/tuning ideas

I just purchased a 2002 Chevy Avalanche, 5.3L vortec V8 with 50,000 miles, runs great but first tank it averaged 12 mpg/city, checked plugs and the gaps were around 60, so I replaced them and the wires with Bosch plugs gaped correct at 40 and replaced the air filter with a free flow K&N type, now I need to squeeze some mileage and a better burn, anyone tackle one of these for the mileage purpose? The only vehicle I have tuned so far is my 02 WS6 (5.7L) with the LTFT's off, I would think this would be similar, braf, maf, ve then maybe spark? Suggestions will be appreciated.

Clean the MAF if you havent yet aswell.

Honestly you won't gain much with a VE and MAF tune when stock but it can't hurt.

It's a heavy truck and kind of a brick going down the road. 12-14 city and 17-18 freeway is about the mileage they get in the 4x4 models.

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Originally Posted by 5FDP

Clean the MAF if you havent yet aswell.

Honestly you won't gain much with a VE and MAF tune when stock but it can't hurt.

It's a heavy truck and kind of a brick going down the road. 12-14 city and 17-18 freeway is about the mileage they get in the 4x4 models.

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I did also clean the MAF, and forgot to mention it is a 4x4 Z71 model, my neighbor has an 05 4x4 and in town he gets about 15mpg when he "drives it normally" I drove mine real easy to see what was the best I was going to get in town and to me 12 sucks! even 14-15 mpg would be a decent increase.

One thing I see looking at the stock tune is quite a bit of spark retard and in the main spark tables the amount of spark drops off quickly as the cylinder airmass increases and goes negative, now maybe the engine will never get to those areas, I don't know but under acceleration I have noticed that the rpm gauge has never gone over 3000 or so, with me so far. When I removed most of the "spark retard" from my 5.7L it did have more pep so conceivably that should help the mpg some?

Would I ever like to get a look at the "hypertech" or "predator" tunes and compare them with my stock :)

After scanning today, the stock tune MAF was fairly close but the VE is way off...5-7 to low, now the VE table is "cylinder airmass" so will higher numbers in the table result is more fuel or less?