Possible bad intake manifold gasket?( Long post)
Hello All, I have a 98 F150 4.6(W) with 225,000+ miles on it. 2 days ago going to lunch the truck started missing real bad. CEL started flashing then stayed on. Pulled a code P0303 Misfire cylinder 3. Pulled the #3 plug and it was wet with anti-freeze( plugs and wires 2 months old).The truck does not blow white smoke and the oil is clean.I did the old test of starting the truck cold with the reservoir cap off and no bubbling or shooting out anti-freeze so I don't "think" it's a head gasket but maybe a intake manifold gasket. Any thought's or suggestions would be appreciated. Also is this hard to replace for a DIY'er ?