Super low mileage - Toyota 4Runner Forum

greembow · 05-25-2023, 11:19 AM

Hey all, I've started seeing a decrease in my mileage recently, from 270 to 200, over about 4 months. 1998 V6 SR5 w/ 249k. I drive super light foot, barely ever above 80, never in ECT PWR mode. What can I do to diagnose this? My fuel gauge doesn't work right, so I'm going by what was on my trip when I ran out of fuel one day.

Help appreciated!!

Twisted Sid · 05-25-2023, 11:40 AM

To many variables and not enough details from you to give any sort of reason.

How long since the last tune up? Have you done any mods to it? Tire size? Are the brakes dragging? Carrying more weight? Put a stupid roof rack on it? Tire pressure change?

gamefreakgc · 05-25-2023, 01:42 PM

Like mentioned above, assuming it is engine related problem here's a list of maintenance items to do:

Check for vacuum leaks. This will kill your mileage faster than anything else.
Replace air filter (can get clogged).
Clean Mass Air Flow sensor. Look for the sensor wires and spray with carb cleaner.
Check spark plugs and replace if worn or damaged.
Replace the front O2 sensor. Do this last as it costs around $60.

This is the easiest way to check for vacuum leaks. You should have a can of carb cleaner to clean your MAF anyway so won't cost you anything but time:

HiLife · 05-25-2023, 01:52 PM

Agree with what the above posters are saying.
When was the last time you base lined your truck?

Toyotas are very forgiving for lack of proper maintenance.

Ignore it long enough and problems will come up.