Jean-Claude Van Damm

For what it's worth, I just replaced my 2006 fx4 5.4l with a 2010 xtr 4.6l 3 valve, and I can tell you that the 4.6l is equal to or dare i say faster than the old 5.4l. I was completely blown away when I first test drove it. I honestly can't tell the difference other than the significant mileage increase I get out of it.

kmac1036

I had a 2010 with the 3v, nothing but solid. Mom's 91 Marquis was really solid too, just the EGR valve clogged on it. the only issues I've seen over the years was the plastic intakes cracking in a couple of places & the clogged EGR. It was on Wards engine list for several years too. GM liked it so much themselves they copied the key aspects of the platform and put into their 6.2.