1999 f150 4.6 i am having a #8 misfire so i changed the plugs, coil, spark plug wires and injector, problem is the #8 plug isnt going all the way down i tried a thread chaser and it help a little but the chaser goes down without any issue tried another new plug to no avail. please help me with this guys
i feel like berning it to the ground right now

 

You sure the chaser goes all the way down? The plugs have 8 threads but the heads only have 4 threads. Is there crud built up on the tapered seat? Is it possible someone has installed an insert? I'd find a way to look down in the hole - mirror and light, or a fiber optic camera.

 

Best i could do with my phone

 

 

 

if they did use an insert would the spark plug size change maybe that is why it only goes down a couple threads

 

Inserts dont generally change the plug size. Kinda does look like an insert to me but its not real clear. Might have to install a bigger insert. Timesert call them big serts

 

Can you take the insert out to change it or does it need to be drilled again

 

contact board member Galaxy. He rents the stuff and can give you the rundown

 

What does the original plug that you removed look like and was it seated all the way down?

 

If it is a Timesert insert that is installed, it is normal for only about the first half the threads of the replacement plug to be used when the plug is fully installed. The insert is not fully threaded on the inside.

 

I checked two other plugs and the go in the same length, I am getting p0308 changed coil, pugs, wires,and injector, code won't go away, compression is good and no leak down I am getting really desperate. At the smog shop before the computer set( I disconnected the Bat) they said it had a pending code p0402 ear flow excessive, would that have anything to do with it. The truck runs great no loss of power that I can tell no stutter or fumble and idle seems to be good, the tac doesn't flutter or anything either

 

Sorry p0402 EGR flow excessive I made a typo

 

i took the #8 spark plug wire of and drove it down the alley and it ran like crap

 

Cleaned the maf and now I am getting p0300 random misfire anyone got some ideas