A bit of history...I bought my '92 VX in April with 139k. All stock and clean. I wanted a federal version, so I bought one in Colorado and had it shipped to California. Right off the bat, it didn't pass smog. High HCs. The car also had the hesitation symptom that seems to be so common amongst VXs. I don't have a lot of spare time to work on cars, so getting my VX to run right was left as a low priority, slow project. Over the last 4 months, I changed the plugs and wires (NGK), installed a new 5 wire O2 sensor and catalytic converter. Turns out the ignition timing wasn't set correctly when the PO replaced the distributor. It was ridiculously retarded at like ~5 deg. BTDC. So I set the timing to factory specs, and the car runs soooo much smoother.
I was averaging 33mpg before this adjustment, and I just filled up after running through my first full tank after the timing adjustment. I got 46mpg! The surprising part? The tires are 185/70/13 and were at 28psi all around. I bumped them up to 43psi all around yesterday. I can't wait to see what kind of mileage I'll see at the end of this tank
Oh, and now my car feels like it has power steering!
Best way to measure your odometer accuracy is to compare your reading to the signs on the sides of the interstate highway if that is possible. Where I live they have them every tenth mile. I just mark down my odometer reading and drive 50 miles measured by the interstate signs.
Example start at 50.0 interstate odo reads 17.3. Dirve until interstate reads 100.0 and odometer reads 66.3. Difference is 1 mile less on your odometer (49 odo-50 interstate). This means your odometer is off by 2 miles per hundred, or 2%.
Just add 2% to your odometer when you figure your mileage. Mine is off by 1% 99 odo to 100 interstate. My tires are 175/70/13 Michelin Xs.
Dont assume your speedometer is off by the same amount. Best way to check it is to use a stopwatch and the same mile markers. Drive at exactly 60MPH and see how many seconds it takes you to cover exactly 1 mile.
60 seconds is perfect. less means your speedo is reading too low and you are going over 60. More means your speedo is too high and you are going less than 60.
This requires real precision driving for 60 seconds. Best done with an assistant on a fairly deserted road if that is possible. Try it a few times and see if the results are consistent.
what I did to verify my speedo was to google search (google maps) how long my trip to work is and you can move around the route until it is exactly the way you take and compare to actual mileage. my trip to work is 19.9 miles one way. and I am pretty much spot on.
this isn't the most accurate way but it is something that can be done easily. another thing is that you can do it several times and take an average of all of the trips to make sure.
Be the change you wish to see in the world
what I did to verify my speedo was to google search (google maps) how long my trip to work is and you can move around the route until it is exactly the way you take and compare to actual mileage.
You can move the route until it's right simply by dragging it with your mouse. Then, once you get it exactly right, click "Link" in the upper right hand corner (just above the "Terrain" button) and save a copy of that link. Then you can go back to your custom route any time.
I use mine when I need to find something near my route home. I go back to the link, there's my route, and I type "hardware store" or "mexican restaurant" or whatever into the search box, and it finds whichever ones are near my route.