I'm building a kitchen table with bread board ends. I built it out of 2x8's cut down to 7" wide and am putting 2x4's underneath as a "stiffener" which I'll also attach to the apron. My problem is I used my impact driver to attach the boards together with 2 1/2" screws. I must have gotten a little carried away and I have several screws that came through. My question is, should I cut new boards and drill new pocket holes or can I just back those out some? Also, if I back out the screws, will I lose holding power on those boards? Thanks!
I've had that problem often with 2x stock and an edge joint.
I would say back them out, put some wood filler in the receiving hole and glue in the pocket holes and change to 2" screws. This will help maintain the strength and give it something to hang on to, however will take some time to dry.
Do it on a test piece 1st. If the 2" still pokes out (it happens) go for 1 1/2".
The issue you are referring to is due to using an impact driver to put in your screws. This will cause them to be overdriven and come through your piece like you are referring to, especially working with pine. You will be able to use the current pocket holes. However, you will need to do something like the wood filler Ronda suggested to allow your screws to grip properly. Personally I just take a toothpick and put it in the hole. This adds enough material for the screws to grip.
The only issue you may now run across would be holes from the screws coming through. These will need to be filled and sanded so that you cannot see them anymore. If you have any other issues please let us know.