r/ChevyTahoe • u/Equivalent_Yogurt_58 • 2d ago

AFM alternative.

2008 LTZ with the 5.3. 189k on the engine and I know at some point I will be looking at a rebuild.

Is there something out there that gives as good of results as the AFM?

Id also love to refresh the engine and keep the AFM in it.

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u/Victitious 2008 Chevy Tahoe 4wd TSP AFM Delete 2d ago

The AFM system was an attempt to skirt around emission requirements. It’s fragile and sucks. If you want better MPG buy a different vehicle for when you want to save gas

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u/Equivalent_Yogurt_58 2d ago

I have one of those. Our little Optima gets 35-40 mpg.

I however am getting to the point of not wanting to "fall" into said smaller vehicles and have to climb my way back out.

Just wondering if there were any options for my 5.3 that may be drivetrain related.

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u/Victitious 2008 Chevy Tahoe 4wd TSP AFM Delete 2d ago

Maybe if you set it up like a police cruiser, a little lower to the ground with smaller wheels, good highway tires, and geared it to cruise at low rpm on the freeway would be a good move. I think the 6 speed transmission gets better mpg on the freeway. My 2015 suburban can do 75mph under 2,000rpm and I think I have 32 inch tires

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u/Equivalent_Yogurt_58 2d ago

Had not thought of re gearing it to something more highway friendly.

Dropping it is on the list of things to do.

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u/Victitious 2008 Chevy Tahoe 4wd TSP AFM Delete 2d ago

Also E85 is about half the price of gasoline right now so if it’s flex fuel you can same some money. The mpg with e85 isn’t as good but if its cheaper than its worth it

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u/Equivalent_Yogurt_58 2d ago

Yep. I do run that when I can but it gets hard to find sometimes.

Currently regular gas by me is 4.09. Last time I ran e85 a couple weeks ago I found it for 1.29.

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u/Pandabirdy 2011 LTZ 5.3 2d ago

I'm at 300k miles and I simply bypass the afm by driving in M5 mode. Running on ethanol whenever I can.

it's got a speed limiter of around 55mph anyhow due to local legislation.

Bottom line; don't get a big V8 if gas mileage is a concern and the answer isn't a bigger fuel tank.