well, I've done a few tanks of gas now, and have come to the conclusion that I'm down about 25KM per $20CDN of gas in fuel economy. Nothing else has been changed on the truck, so I'm assuming somethings gone wrong. (91 K1500
305)When I had a TBI problem (FPR), the truck ran disgustingly rich, black smoke, etc all the time. it was obvious. but this time the truck only smells slightly rich on startup, and after warming right up doesn't smell rich at all...
can a failing O2 sensor allow a /somewhat/ rich mixture, not bad enough to smell outright, but bad enough to hurt fuel economy in a measurable way? what other symptoms are there? the truck runs and drives perfect otherwise...it was changed to a Delco piece January of 2002. so its not even got 2 years on it....is this normal??
b