That's strange. Apat from the handbrake being on and possibly a door being open (?), I don't think the red triangle light would come on under normal driving if there weren't any error codes being logged.
It sounds like you've got more pressing issues than the warning light (i.e. get the fueling/ECU sorted out), but it also sounds like your other warning light isn't working too. When the red triangle comes on, do you also get the orange engine symbol light (the EML) come on too? I would definitely expect this to come on, and if it doesn't, it's probably caused by a dry solder on its circuit board: common problem.