We don't think we could count the number of classic cars, both original and hot-rodded, that we've seen with an improperly working or broken gas gauge. We know it's a pain to drop that dirty old gas tank down and see what's going on. We spoke to Ross Ortman of Dakota Digital (800/593-4160, www.dakotadigital.com) and he says the most common reasons a stock sending unit reads wrong, or not at all, are that they may be rusty and stuck, or there is a bad ground. Many old cars relied on the tank touching the body of the car for a ground connection, which just ain't cuttin' it. For many updated cars, the biggest problem is the lack of attention given to the calibration instructions provided with the new gauges or sending unit. If you don't have the time to do it right the first time, when will you have the time to fix it? The next issue would be having a non-compatible gauge and sending unit combo. The bottom line is to talk to the manufacturers to make sure everything is compatible, and then to get off the couch and follow the instructions.