Problem started when the fuel supply was low, she had to floorboard it to get on the interstate, keep getting cel, misfire #4.....I replaced fuel filter, had a little water causing the plug to arc....had a mechanic replace the plug.....at startup cold, cel is off and it doesn't miss, after it warms up, light comes back on and starts to miss. I have ran every type of fuel cleaner in it, even used a three step cleaner for throttle body, vacuum system, and tank. I just poured sea foam into the tank and trying that, I noticed a gurgling noise when I removed the gas cap. I'm thinking #4 injector is stopped up......can anyone give me advice? I recently replaced all the coil boots.....kept getting condensation in the boot (she has been washing the underside at the car wash).....the truck has the 4.6 and has 85,000 miles, it is an 07 sport trac.....

 

I'd suggest you swap the coil from #4 with another cylinder and see if the misfire remains on #4 or follows the coil. It's not uncommon for these coils to fail, especially if they've been arcing to the head frequently due to water and/or bad boots. You might swap the plug with yet another cylinder as well, kill 2 birds with one stone. If the misfire follows the coil, replace the coil. If the misfire follows the plug, change the plug(s). If the misfire remains on cylinder #4, do a leak down test on the cylinder and if that passes, swap fuel injectors around or replace the injector.

-Rod

 

I moved # 4 coil to # 3 spot and still get the #4 misfire code, next theory would be the injector. Where I can find step by step instructions for pulling the fuel bars and moving # 4 injector to another location......still looking for the bug........if I had some good instructions, I think I could perform the operation myself.......just trying to save a few bucks.......