[freakshoww]

Originally Posted by Ryland

How much of the exhaust system did the car have replaced? that would be first on my list of things to fix, after of course making sure that it was otherwise running right.
Add to your list, changing transmission fluid (0w30 motor oil, or Honda MTF), clean points on distributor cap, check timing, check under the hood for other mods done by teenagers.

It looks like only the axleback has been modified with a simple bolt-on.
I'll add those to my list, and it looks like there aren't any other mods under the hood except for an aftermarket fuel filter.

Originally Posted by hamsterpower

The first thing that comes to mind, jack up the back end, with the hand brake off, and spin each back wheel. Look for sticking or rubbing brakes, wheel wobble, noise, etc... I've had wheel bearings go bad and sticky parking brakes drag.

Also look over the tires for scallops or cupping that might indicate a bad alignment.

Third- wipe your finger inside the tail pipe. Is it oily? Bad seal/ring or too rich.

These checks should be fairly quick and free.

I will add these to my list. Thanks!

Originally Posted by Ryland

You should check your tire pressure a few times a year so if you haven't yet then it's most likely low, combine that with the wide, non LRR tires you have and you'll see a few mpg drop right there.
On the two VX's I've owned I've noticed that exhaust issues and non stock exhaust seems to lead to the o2 sensor failing, so you might not be able to revive a failing o2 sensor but unless you want to replace it twice, like I ended up doing on my first vx, I would fix the exhaust with stock parts first.
Also, does your VX have any dealer options? passenger side mirror, mud flaps, or A/C? each of those will cut your mileage back a little, not as low as you are seeing but they all have an affect.

The tire pressure was a *little* low. 33PSI on a 35PSI max tire. I put them all to 37 for now. I will also try to exchange my muffler for a stock one. Is the VX muffler different to the regular EG muffler?
The car has no AC, no mud flaps, but it does have a passenger side mirror.

Originally Posted by Old Mechanic

How long is your commute?
What is the average speed?
Unfortunately the VX loses lean burn capability for a significant amount of time after engine shut down, which eliminates the lean burn advantage, as well as potentially making the 02 sensor cool off and possibly not give you closed loop.

Unfortunately my commute is currently mostly city driving. It's about 4 miles at about 30mph (city driving, but not bumper to bumper). I do drive plenty outside of my commute too, but rarely on a highway.

Originally Posted by Old Mechanic

How long does it take to warm up-possibly thermostat not closing properly?
EGR circuit clogged?
Top gear in the original transmission should give you about 35 MPH at 1000 RPM and the car should pull away from that speed even at that low RPM. Short shifting is an essential part of VX mileage, unless your speeds are just to low.
Look at Pale Melanasians mileage on his DX. It has none of the design advantages of the VX except it is also a Honda.
His mileage would probably be lower if he drove a VX, due to the low average speeds and high rates of DFCO. The Vx systems were designed more for prodigious highway mileage. On mine I did well in the city but I did not use DFCO, knowing it's effect on lean burn and 02 temps.
Tires are also a crucial part of the VX package. I could push the car on flat smooth concrete with one thumb.

regards
Mech

I will try to time the warm-up and check the EGR circuit (have to google to find out how). I'll also try to push my car, although it doesn't have the original tires.

Originally Posted by jakobnev

I'd check the part of the HT-leads that go down to the plugs for cracks and damage.

Just checked, my spark plugs are the ZFR5F-11 plugs (replaced by the dealer). Google seems to indicate that those make a fairly big difference to the proper VX plugs (ZFR4F-11?)