My son and I changed the spark plugs in my 2004 F-150 Lariat with the
5.4 Triton V8,v3 engine. Thankfully, we got all 8 plugs out without breakage.

We do have a problem. There is an extra wire that we do not know where
it goes. This red wire come out of the coil/plug harness near the fire wall.
The end of the wire had a trumpet appearance and was about the size of
a dime. In the center was a round object about 3 millimeter in size. Over
all this terminal was very clean. The truck seem to be running fine.

Could anyone tell me where this attaches.

Thanks

 

Are you sure its a wire , and not a small hard vacuum hose ?

 

No, it is not a vacuum hose.
Thanks for asking.

 

Well, I really do not know for sure. It just does not appear to be a vacuum line.

 

What side of the motor is this on, Is it just s single wire? I have a connector that hooks to the OPS under the intake, and some tritons have there knock senors mounted under there and more info and I will look under my hood again and see.

 

I checked my 04 again, the only thing I see on the passenger side is the red vacuum line that goes from the intake to the purge valve (MOUNTED ON FIREWALL) to the vacuum can.

 

Thanks Dave7.3 I will look and see if I can find it as you suggest.

 

I would bet it is the 2nd part of the vacuum line that goes from the back of the intake on the passenger side to the fuel pressure valve

 

You are exactly correct Dave7.3. The trumpet looking part is part of the
purge control valve. ( I saw the part in parts catalog)The redline is a vacuum line.

Now to find this purge valve. Could you give me a little more instructions
on it exact location. Then I will have the job done.

Thanks Dave7.3

 

That red vacuum line goes to the 4wd hub solenoid and is not plugged into anything on 2wd trucks. The purge valve is on the driver's side next to the brake booster

 

Thank you for your reply.