[sledgehammer357]

My 03 F150 with the 4.6 Triton engine was throwing a misfire code on #3 cylinder. I changed plug and coil. I am losing antifreeze. At first no steam in exhaust, but now there is. Compression is holding at 160 in #3 & #7 cylinders. Pressure checked cooling system and it held. When I pulled the #7 coil, the plug boot was rusted and the spark plug tube was filled with water. The plug smelled like fuel. When I pulled the #3 plug, the plug was wet with what appears to be water. Any ideas on what it could be? Thank you for any help.

[aalv3]

getting any bubbles in the coolant when the engine is running? water in the spark plug holes could be as simple rainwater pouring down from the cowl, i've seen it several times, seems to be pretty common as cylinders 3 and 7 are towards the back of the motor an coincidentally right across from eachother.

[aalv3]

also, i'd pull all of the plugs out and see how they look if you're losing coolant and there's no external leak. wouldn't hurt to do a compression test on all cylinders as well. usually when you're burning antifreeze it'll have a steam cleaning effect on the plugs. it's possible that your misfire and your coolant leak are two different problems. don't limit your search to ignition failure either, get a screwdriver and put it to the injector and to your ear, should hear a loud clicking. although if you say the plug smells like raw fuel, i'd rule injection out. good luck!