Another gauge corrector--cheaper than MeterMatch, 33.00

I put a meter match in my other hobby car (85 Celica Supra) and sometimes it works perfectly, other times it shows way lower than the actual fuel level.

I have a pretty good idea how much gas is in the car at any given time because I use the motorcycle approach like @LocuMob, and the car gets a pretty consistent 19 - 20 mpg. So I know at 200 km I'm just above half a tank and once I hit around 400 km I had better find a gas station and avoid steep hills.

Last time I filled up the gauge went to about 5/8 or 3/4. Drove home and parked it for a week. Next time I got in the car the gauge was reading full. Was good for about a half hour then dropped to 5/8. Once I got that tank down to about a quarter tank the needle was dropped way below E. In between that time there were wild fluctuations between where it should be and way below where it should be.

I was going to reconfigure the thing but after reading these comments I'm thinking they're not the greatest at doing what they're supposed to do, so I'll probably just leave it alone.