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Hi All,
Got a puzzle on my original owner, bone stock 2001 LX sedan. 330,000 km.
My mileage is all over the map.
The car is used for commuting and 99% highway driving.
I used to get pretty steady ~6L/100km range then I had a brake caliper lock up on my ride home. After that, it's just never been the same.
The weird thing is that I'll get a good tank, followed by a terrible tank. Over and over. This makes me think it's nothing to do with the brake.
Only codes I have are purge solenoid valve P1457. And the rare torque converter lockup code.
Could it be how the tank is venting during fill ups?
I added a screenshot of my mileage tracker for effect.
Edit. Not sure why my photo isn't showing up here or on my reply. But it looks like a sawblade. Up, down, up, down. Week after week.
Last edited by Markman34; Sep 28, 2022 at 11:05 PM.
What's the scaling for the vertical axis? I can see it's not consistent but I have no idea the difference between a peak and valley. Start checking brakes after a drive. If one is sticking/dragging it will be noticeably warmer than the other side. The pump could also be occasionally stopping early making fuel economy look bad.
The range for the mileage is between 9 l/100 km and down as low as 4.5. It used to be rock solid week after week.
I did notice the passenger side caliper hotter than the other and that was my thought at first. But when the peaks and valleys became so regular I wrote off the dragging brake theory as it would be a constant.
I have adjusted my filling habits and now fill slowly at the pump.
Based solely on the economy you're seeing, I would guess the pump is sometimes stopping early. The car is rated for ~6.7 L/100km (35 mpg) highway and ~8.4 L/100km (28 mpg) city. If you were able to get 4.5 (52 mpg) on one tank, I would guess the pump stopped early making that trip look very efficient. The following tank (assuming the tank fully filled) would have had much worse economy since it has to fill up the amount used plus whatever was missed the previous tank.
In my CRV the pump will sometimes stop early. If it seems like the pump is filling quickly, I often set it for the first notch so it goes a little slower. You could also try that. Alternatively, don't reset your trip and just keep track of how much fuel you put in. After a few tanks or couple thousand kms, calculate the L/100km. That should give a more accurate reading if the tank doesn't always fill up.
