Thread: Engine missing all over the place... - Crownvic.net

Yea, there was a very tiny bit of of the head on the #3 plug. It was very minor, but now I can hear a slight rhythmic hiss that follows RPM to about 2000 RPM. Every now and then, the idle will get rough and then pick back up.

ive never had that issue before with a 4.6 i guess its only a few in a hundred ive owned maybe 7 or 8 4.6 V8's

 Originally Posted By: RPnhis2004CVPI car is going to the mechanic tommorow. And they're gonna run a compression test on me hmmm wait, i have seen like that before, you may have a blown head hasket between 2 cylindesr causing misfire.

The problem with that is the head is the issue and the Motorcraft happens to make a great quality x2 plat spark plug that is recommended here for stock cars. It's akin to saying "All the cars with this problem were running Motorcraft Coil-on-Plugs." We got the shaft when it comes to head thread count.

ok if you disconnect a differant one does it idle even worse?

I do not think it is anything like a engine. Its just too close to when you replaced the COPs. Im still going with one or more of the connectors is corroded.

Check the fuel injector and COP connections. Had a loose fuel injector connector on mine once and it would miss occasionally in idle and if I hit the accelerator anything more than granny-style. Pulled over, pushed on all the connectors, and ran great again.

Maybe it's a bad injector. I put in some fuel injector cleaner once (probably too much) and I think I dislodged some crap that went downstream into the injectors. My fuel filter was well over due to be replaced Mine was missing on 2 and 6. I took it to ford and they said i needed a new 1 and 5 injector. I replaced all 8, got a new fuel filter and problem solved!!! ps: what dripped out of my fuel filter was as black as a tire.

I had a similar problem with the 4.6L in my 02 F-150. It blew the electrode and ground strap off of the plug in cylinder #3 and the plugs were Motorcraft (replaced about a year before). When I replaced that one plug and ran it for a few seconds, there was no change-but the new plug was drenched in oil! The area around the sparkplug hole was so severely 'eaten-away' that I could see almost 3 threads on the sparkplug (after I removed...