Top Answer
User Avatar
Wiki User
Answered 2008-07-12 15:06:18

Ford's spark plugs on 4.6 and 5.4 engines from 1999 to 2003 have a design issue that make the spark plugs prone to blowing out. There are only four aluminum threads that hold the plugs in. The Ford dealers will want to replace the heads rather than repair them. Thin repair inserts may blow out again, so using a thick proven repair insert is recommended like the Calvan 389-100. Speed shops use them when modifying and rebuilding Ford 4.6 and 5.4 engines, the repair lasts the life of the engine. It could be a faulty plug or a vacuum leak that causes the cylinder to run far too lean. Replace a couple plugs, run it for a few miles (20 to 50) then pull the plugs and see what color they are. If the plug in the cylinder that failed is too bright, you're probably running lean from a vacuum leak. Unless you mean the plug simply came out of the head. If so, maybe it just got left loose and eventually worked it's way out. Also possible the threads are stripped out of the spark plug hole and the plug actually blew out. Take a look at the threads and see.

User Avatar

Your Answer

Still Have Questions?

Related Questions

Where are the spark plugs in a 1999 Ford F150 5.4L?

Screwed in the heads.

Where are the spark plugs located on a 1999 Ford F150?

they are under the little circle black things which are called coils

What is the spark plug wire diagram for a 87 ford f150?

That would depend on which engine size you have

Spark plug gaps 1999 ford f150 4.6l v8?

.054 inch - according to ( one of Fords websites )

1999 ford f150 removing fan shroud?

To remove the fan shroud from the 1999 Ford F150 you need a user manual to guide you.

You are hearing a whistling noise on your 1999 Ford F150 What would cause this?

The head gasket is about to blow.....Typical ford..

Why did spark plugs turn orange color on 1999 ford F150 truck?

sounds like the motor is running lean, not enough fuel.

What would cause a 1994 ford f150 truck not to start?

There are a couple of a reasons why a 1994 Ford F150 truck will not start. The truck may have a dead battery or the spark plugs need to be replaced.

How do I remove the spare tire in a 1999 Ford F150?

Removing the spare tire from a 1999 Ford F150 is simple. All you have to do is get under the truck and unbolt the spare tire.

Where is the spark plugs on a 2000 ford f150?

i know if you have the 5.4L V8 you will have coil packs. not spark plugs

What is the gap for spark plug on a ford 1980 pickup f150?

.044 inch

What is the spark plug wiring order for a ford f150 1985?

for what size of engine ?

How much freon in 1999 ford f150?

2LB. 12OZ.

Does a 1999 ford f150 have a sight glass for the transmission fluid?


What is the spark plug gap for a ford 2003 f150 4.6L Triton engine?


What is the spark plug gap on 1984 ford f150 8 cly?

.044 inch

Spark plug gap for 1992 Ford truck F150 with a 351?

.044 inch

What is the spark plug gap for a 1994 Ford F150 300 six?

.044 inch

What is the OEM TIRE size on a 1999 ford F150?


Where is the turn signal relay located on a 1999 Ford F150?


How do you reset anti theft on ford f150 1999?

To reset the anti-theft on a Ford F150 1999, put the key in the ignition. Turn the key halfway and leave it in that position before starting the car.

What is the spark plug gap for a 2001 ford f150 v8 5.4 liter?

.054 inch

Does a 1999 Ford F150 4.6L V8 have spark plug wires?

Yes , its EDIS ( Electronic Distributorless Ignition System ) so it should have spark plug wires ( I believe in 2000 the 4.6 L went to Coil On Plug - C.O.P. )

Where is the crankshaft position sensor located on a 1999 Ford F150?

forward of the firewall

Can a 1999 Ford seat fit in your Ford f100 1978?

can a ford f150 seat fit in my 1978 ford f100 custom truck

Still have questions?