[SSssnake]

ok guys.... i have yet to clean the MAF or change the o2 sensors (i will run through the codes with another shop to make sure that is the problem..) so i decided to start the tune up with new fuel filter and new plugs (both from motorcraft).... when i was done changing these two things... cranked up the motor and there is now this "murmuring" sound to the engine... WTH is that??? how does pinging or detonation sound like???? ive never had experience with those problems.... also... the sound might have started before i changed the fuel filter and plugs ... its just that this was the first time in a LONG while that ive heard the motor running with the hood open.... i have no clue wat this is... please help! on a side note... it sort of sounds like an exhaust leak... very low.. sort of bass-like sound.... so its low in tone but is considerably loud (could just be that im sooo paranoid)

[SSssnake]

oh yeah ... jus to add to this post.... to make sure installation was correct.... plugs : took of the wire and change each plug one by one... so i know i didnt criss cross any wires.... simply removed the old one.. and screwed the new one in... DONE! fuel filter.... the car has an external fuel pump by NOS (previous owner ran the car with nitrous)... so i disconnected the line from that fuel pump going to the filter... unbolted the bracket holding the filter.... took off the platic bracket holding down the hose to the neck of the filter... pulled out the filter... uninstall done..... installation was just everything backwards....... one thing im worried about that i did wrong was when everything was done... i cranked up the car right away instead of putting the car in the on position to let the fuel pump ... well pump fuel thru the empty filter... was that a bad move and would that cause the "murmuring sound".... also... would the way i installed the new filter cause a change in fuel psi?!?!??! thanks in advance
joe