Oh my....you sound so like me earlier this week when I posted a problem about my Janome and FMQ....I was at breaking point ...when Annaquilts suggested leaving the feed dogs....WOW what a different...I think I may have to take my machine in for a tune up though after messing so much with the tension....I haven't got a clue wether it is right or not because I have played with it so much! But tonight......Feed dogs up....away I went....first time since I have had this machine ( 2 months)....beautifully balanced FMQ with lovely tension front and back.....way to go so happy....did the whole border of a baby quilt.
Just keep perservering....ask loads of questions and someone on this board will have the answer for you.....Good luck