My 1990 vanagons GL is getting a poor gas mileage

Hello there!!Well,you must notice that the gas indicator kinda sucks really.It sometimes shows that you have a lot of petrol in the tank but as you drive along you may start to realize that the indicator has almost gone to its lowest,almost empty,there i guess is where you see how your mileage has dropped.Somehow,vanagons tend to waste quite alot of petrol,more than what u might expect,but this i would reckon is about what i just mentioned.Also,vanagons arent meant to be fast,so,anytime when you go from still,we normally tend to press hard the throttle,even more in this car due to its lack of speed.My advice would be to avoid going to hard on first gear and try not to exceed 3200 revs,this will save some petrol.Everytime you see your gas indicator whether dropping or going up while driving,wait untill you go in a still position and then let it go back to where it should belong for a couple of seconds,theere youll see your actual amount of petrol in your tank.Now,the average mileage decreases as elder the car gets.Hope it works.As soon as you realize what was it,let me know!!Later!!Good luck!!

Thank you for your advice. This really help a lot. I also recently had a complete tune up and now improves my mileage. My mechanic told me that it's running too rich in fuel. He also did a compressor test result as: 150,160,150,150. He will need another test on my low fan sensor on my next appointment. I told my wife to give this van another chance to leave and she agreed. So far, it's running smoothly and the gas improves.

catalytic converter possibly failing try disconnecting wires coming from exhaust pipe

This happened to mine and it was something really simple/easy to fix. A wire to a sensor had come loose in the engine, causing it to use too much gas. $130 to fix and now my gas mileage has greatly improved.

Body to engine ground strap, located near the ignition coil. If it doesn't have a good connection, the van runs rich.