Hello

My brother recently got a 1999 v8 4.6 2wheel drive f150

After 2 months with it, he was driving on the highway and the #7 spark plug blew out.

He took it to a small town mechanic and they replaced the plug and the cable and sent him on his way.

Now its misfiring in cylinder 7 on and off.. Code 307. Its only when the engines hot. Starts and is continuous until you get it up to like 60-65 mph or keep the revs above 1700, then it stops until you put load on it. There is also a relatively loud ticking noise from the same cylinder. sounds like it could be valves.

I swapped the coil packs (it doesnt have COP) and it made no difference.

What should i try next? Could the plug have fd up the valves on the way out?


Thanks for any help!

 

Sounds like the plug broke again, but it could be very possible that whoever fixed it didn't get all the ceramic/metal out of the cylinder and it caused a problem with the valves...especially having taken it to just a small town shop

 

Is there an easy way to tell if there's metal inside? or get it out?

 

Well after its been running it's either worked it's way out or has embedded itself into pieces of the motor. You can get an inspection camera, take the plug out and look at the inside of the cylinder to see what it looks like. But I don't think that's going to have the answer you're looking for since it doesn't reveal much other than the condition of the cylinder walls and top of the piston. If you REALLY wanna get into it...you can take the head off and inspect the whole damn thing. But that's a lot of work for probably a simple issue.

 

Tighten the plug before it blows out again. You probably have to get it fixed right at some point.

 

Yeah, like Jbrew said, make sure that plug is tight for now... and you'll probably need to Timesert it to get it fixed correctly.

 

I think he ^^ meant "plug". So yea, you can leave the pigs be.

 

Thanks guys!

 

Let clarify some things.
My info shows a 1999 4.6L F150 has COPs.
What did the mechanic use/do to fix the plug?
Did the mechanic just chase the threads and screw in a new plug?
He should have used something like a Timesert to repair the head.
The COP would probably have to be replaced, but what "cable" was replaced?
The ticking noise might be exhaust leaking past a loose spark plug.
You swapped coil packs - did you change the coil,boot and spring?

 

Your info is incorrect.