Feeds too much paper - HELP

Hi

Had a good look in the forums but most paper problems are paper not being picked up whereas i have too much paper being picked up. I have a dell 3330dn laser printer and the problem is that while the printer is printing 1 page, it will pick up extra sheet of paper while the 1st one is still being printed. While the 1st page is about 30% being printed, it will pick up a 2nd page and then when the 1st page is about 60% of its way being printed, a 3rd page will start to make its way through the printer.

The first page prints normally but the second or third page have nothing printed on them (because nothing is supposed to be printed on them anyway) and this all results in a paper jam. When the first page exits the printer THEN it realises there is a problem and it comes up with the error and tells me exactly where the jams are.

I thought it is just a matter of paper type setting but I don't know what setting I should have. I changed the paper weight to "light paper" but that just made the paper jams more closer together with about 4 sheets being jammed instead of the usual 3. Then i changed it to heavy paper setting but that makes the jam happen with every page I print whereas originally i could print 2 or 3 pages before the extra paper jam.

Any clues?