I've always considered myself a decent baker, but in the last 6 months, I've had trouble with several cookie recipes that I have previously had good luck with. The dough seems to come out very soft and gooey, even after chilling, when it is supposed to be stiff enough to roll - either in balls or cut-outs. I use margarine, but it's never been a problem before. I occasionally substitute some whole wheat flour for some of the white flour. Any clues?
Whole wheat flour isn't going to absorb the same amount of water as white flour, so that's probably the source of the problem. You can either add a bit more flour until you get the right consistency, or reduce the amount of liquid. Margarine counts as liquid as the majority of it is water, so reduce that and maybe add less egg. If it was me, I'd just try adding a couple more tablespoons of flour and see if that fixes it, don't add too much extra right away as you'd be surprised how little flour it takes to change from gooey to firm.
Uneven temperature of the oven might also be the culprit. Too much frequent open visits to the oven can drastically vhange the oven's te peratre, which gives more time for the dough to spread out in a hot environment because its uncooked. Id give this a shot, if not for the wrong recipes with too much liquids.