Ford 4.6 V8 spark plug question

Misfires in these are more often than not caused by a coil going bad. Never had a plug related running issue with it.

was/is there a problem with the earlier 4.6L ('97 F150 ) on the intake it says 4.6L Triton … nothing about how many valves ?

note to self...

Well the deed is done. I bought the broken plug extractor tool before I even started , as insurance, and it paid off. Not one broken plug.

I did it with the engine warm and a good shot of PB Blaster down in each plug well. A few of them fought me, but working them back and forth did the trick, and a couple came out so easy that I was sure they were busted, but they were OK. All the new plugs got a good coat of antisieze on the way in.

All in all, not nearly the worst plug R/R I've done. The misfire is gone, and now you can clearly hear the exhaust leak from the broken exhaust manifold bolt

dean1484 wrote: Misfires in these are more often than not caused by a coil going bad. Never had a plug related running issue with it.

Coils going bad is usually because the plugs are worn out, increasing the required voltage to jump the gap. This overheats the coils.

100k mile spark plug service intervals are really bad for coil life. When we see a coil fail, if the plugs aren't new then we recommend new even if it has "only" 70k on it or so. And if they don't opt to replace ALL the coils, the new coil gets installed in the most PITA spot, to make it easier to replace one of the old coils when they fail.

Sometimes you get lucky. Last month I saw a 260k mile 2v that the owner was actually proud that it still had the OEM plugs in it. Well, seven of them were in it when he brought it in...

I bought my F150 ('97) 4.6L (I'm guessing 2v since that seems to be what Ford was selling as 4.6's in '97 trucks ) about 18 mo ago … the PO said that they had changed the plugs … I've put about 10kmi on it since purchase … (total = 120k)

since I can't get with the PO, and don't know what they did during the plug change… would it be worth it to pull the plugs and use liberal amounts of anti-sieze and re-instal ? or let sleeping dogs lie ?

wbjones wrote: I bought my F150 ('97) 4.6L (I'm guessing 2v since that seems to be what Ford was selling as 4.6's in '97 trucks ) about 18 mo ago … the PO said that they had changed the plugs … I've put about 10kmi on it since purchase … (total = 120k) since I can't get with the PO, and don't know what they did during the plug change… would it be worth it to pull the plugs and use liberal amounts of anti-sieze and re-instal ? or let sleeping dogs lie ?

Sleeping dogs lie, you've got the 3 threads/plug that get thrown out. BUT if you hear what has a tone of a lifter tick, but has the frequency of a rod knock, then you've got a plug backing out, Change it ASAP!

ok, thanks … the only sound I have now is what sounds like a leak in the exhaust system … but it's weird … when first starting off (i.e. cold) it's fairly loud … after the truck warms up … sound goes away … like I said weird (haven't gone under the truck to try to pinpoint the leak)

I tell this, because I've never had a rod knock (in anything), so wouldn't be sure what the sound would be

oh … and you say change it … as opposed to turning it back in ?

In reply to wbjones: Could it be a loose or broken exhaust manifold bolt? The mountaineer that I just worked on has a broken manifold bolt, and the noise goes away after about 5 minutes of running, when everything heats up and expands.

Just have to love the cast iron manifold and aluminum head deal. It must be the OHC design as the 4.7 loves to so that too....

HappyAndy wrote: In reply to wbjones: Could it be a loose or broken exhaust manifold bolt? The mountaineer that I just worked on has a broken manifold bolt, and the noise goes away after about 5 minutes of running, when everything heats up and expands.

very easily could be that …. there is NO way the exhaust manifold could ever be taken off … the rust has eaten away the bolt heads/nuts … which ever … all you can see is a gob of rust and really nothing else … well actually they could be gotten off … but replacement would be a bear

the truck had been driven every day by the PO, without regard for all the salt they use where he lived … and NEVER EVER washed the underside … it took a torch and a 3# hammer and a couple of hrs to remove the front calipers … the entire brake system had to be replaced, from the booster to the soft lines (replaced them just 'cause) … the only parts that were still good were the rear drums themselves

Ranger50 wrote: Just have to love the cast iron manifold and aluminum head deal. It must be the OHC design as the 4.7 loves to so that too....

SBCs and BBFs and everything else that sees lots of load with a loooong exhaust manifold will break studs.

Heck, my VW's exhaust manifold is held on by only four out of ten, the rest are broken. Loooong manifold and the engine lives at WOT.

So this week a 3v F150 comes in and the guy wants us to get the maintenance up to date. He bought it used and does not know if the plugs were ever done. The plan is, remove a spark plug and see if it's OEM or replacement.

So, following the New Learning, I get the engine warm, remove a coil, insert a 14mm spark plug socket and the shortest extension I can manage, drop my 3/8" impact gun on it, close my eyes tight, and gently reverse the gun.. and... ANNNNND.....!

I shelled the plug. It didn't break off, the threaded shell removed itself completely from the porcelain. The complete porcelain was still in place. The socket contained a hollow threaded tube. If I was confident that the remaining portion of the plug was grounded to the head, I could have just put the coil back on and (gently) drove the truck back out. Never seen then do that before.

Oh well, we were expecting to have to do plugs and have to extract them anyway. When it comes to questioning if 3v plugs weren't done yet, it's like DeNiro said in Ronin: If there's any doubt, then there is no doubt.