TeamSwift

Hey I have a 93 Geo Metro xfi. Gas mileage is terrible. I live in Northern Minnisota. -30 yesterday morning and it was running rich with black soot in the snow below the tail pipe. Had to drive 120 miles. Took over half tank of gas. Won't idle at stop sign. I figure maybe map sensor, 02 senson " but shouldn't matter when cold before reaching operating temp ", or maybe temperature sensor. Any ideas? Bajo

How many miles are on it? Sounds like what mine did with about 140,000 when it ate up its first exhaust valve. Check your compression if you can. If its low thats your problem. I have two metro xfis now and when I got the second one it had the same exact problem as my first and as you describe.

Have you checked the standard things like your plugs/wires/cap/rotor/aircleaner?

I'm in Alaska and its been below -10 to as low as -34 for the last 3 weeks, both of me geos run quite cold and a bit less fuel efficient but otherwise run fine.

Sounds like excessive fuel pressure or maybe the fuel pressure regulator diaphragm has split? If you have a fuel pressure gauge, check the pressure first. If not, just remove the four torx screws (careful, they break easy!) on the regulator and take a look. With those symptoms my first thought is either the diaphragm is shot or you've got a blocked return line.

Greetings from a northern neighbour.

I had similar symptoms on my 1991 Sprint/Metro and it turned out to be a burned out exhaust valve in cylinder 2. Basically what would happen is that most if not all of the fuel in cylinder 2 would end up getting pushed into the exhaust during the compression of that cylinder and out the tail pipe. This robbed power obviously, but additionally the fuel in cyl 2 would absorb heat from the rest of the engine but not create any heat so the engine never warm up, it ran poorly at lower RPMS but I think cylinder 2 would still fire a bit at higher RPMS as the fuel didn't have time to escape before the spark so it seemed to run ok at higher rpms.

I got really crappy mileage until it was fixed. If you check your compression, that will tell you for sure if you have a similar problem.