anything is possible. I don't think it's the spring because the nfs aren't a super aggressive drop. Did you do the install yourself? The spring may not be seated in the perch properly. I have tanabe springs on 3 cars not and always recommend them to friends. Good price and great quality and great for daily driving. I also have Gfs on my project car
http://www.tanabe-usa.com/nf210.asp?id=2