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'99 Chev. Suburban 5.7L 

Dear folks at AquaTune,I am one happy camper. I have a big '99 Chev. Suburban with 5.7L Vortec engine. The best I could ever get out of this rig was 15 mpg and that was babying it and not towing anything. Now, I am getting 20+ mpg at 75 mph and that includes towing a trailer. The horsepower will put you back in your seat. I have also noticed that the transmission isn't downshifting anymore going up the steep grades and the engine is running a whole lot cooler. I was so skeptical at first but, now I am a believer. Thanks,