well I have been driving the Tracker full time now that I put the Reatta away for the winter. I just think the Tracker isn't getting the optimum MPG. I only seem to get 18-21 mpg

newer plugs wires and cap and rotor
the tires are alittle bigger but should throught the trip off too much so maybe 18-22mpg

when the truck is cold I get some spark knock that can be heard inside the cabin, but as soon as it warms up it runs great.

no check engine lights, I think the Coolant temp sensor is messed up though. (only reads 1/4 gauge warmed up)

only about 180-190 miles per tank.

1990 1.6 8v 5 speed 4x4

Maybe a restricted exhaust??

here's a link to the gas mileage other members are getting...http://www.zukiworld.com/forum/index.php?topic=8044.0
Myself i was getting some where around 22 with a bad head on a 90 tracker.. hope this helps a little..

no restriction there! no cat and a free flowing muffler
3" cone filter and tubing

Sounds about right for an 89-90 with an auto trans,
a little low for a 5 speed, but not too bad.

What you think is spark knock is actually piston slap,
and I would suggest you let the trucklet warm up
before getting on it in the cold weather. Also use 5-30
weight motor oil, I would use 0-30 if I could find it in
other than Mobil1, great cold weather starting oil.

You could advance the timing to about 12* advance,
that should help the performance some, but I think you
might be running a worn engine, and your mileage shows
that the engine is working harder and not getting 23-28
like others have got with a 5 speed

Wild

the truck runs great! it sure sounds like spark knock!

what tire pressure are you running?

My MPG drops to the low 20's when TP is set to "factory recommendation".

When I pump up to about 32 psi, I get about 30 MPG (25 to 27 in cold weather).  Rides like a brick, but worth it in my opinion.

'96 1.6 16v 5 spd on 225x15's

I will check the TP...