After my MPFI Conversion, I decided it would be good to also change the fuel filter. I have done this before with minimal mess and spillage. This time, however, I had a very different result, despite the fact that I had bled the pressure from the system during the MPFI install. I went through the usual procedures, cracked the front fuel line nut but it seemed like extra fuel was spilling out...too much for a depressurized system. I then cracked the rear nut and after the usual spillage, it just kept flowing. The worst part is that I had bought a K&N fuel filter and I could not get the rear nut to seat and the entire time I am getting doused with fuel. I reinstalled the old filter and took it to a quick oil change shop the next day. They had the same issue. Some background: 12 months ago, the Yukon would not start in the middle of a trip. After a tow to the dealer (I do my best to avoid dealer's ever), my faithful fuel pump had died. They dropped the tank and replaced the fuel pump. A more expensive job than I had wanted to do on my trip. I have not replaced the fuel filter since after my dual battery install. The quick oil change tech said it seemed like the fuel pump was still active even with the key off. Any thoughts on: 1. electrical issues that might cause this either as the result of my dual battery work or the dealer's replacement of the fuel pump. 2. diagnosing any electrical faults/shorts that I could start with before I bring it back to the dealer who swapped the failed fuel pump? Thanks for the help!