mdelao

i have only 2 months with my 2000 GT mustang, the stang runs good!! but i have a complaint with MPG, I around 15 MPG (most city diving) the car has 80k miles not too much, engines doesn’t have any mod, just K&N filter. I realize that the car has like three different coil on plug: stock ones, valuecraft and troyan, even one of those hasn’t the bolt to hold the coil. I was researching to chage all of them and I found on AM the MSD, Accel also seen the steeda Can somebody recommend which is best the buck (quality/price)?

I just ordered a NGK iridium Spark Plugs but I’m still wondering if would be a good idea to replace all coils… would this help me with the MPG issue?

mdelao

Somebody ?

cpotts13

I have the same year gt with a manual transmission. Its always a good idea to change the spark plugs when you first get a car. Ad for mpg, try a fuel injector cleaner. I typically get 16mpg or less though...

Glenn

use a tq wrench when you install your new plugs

cpotts13

How tight? I may be replacing mine soon..

cdynaco

wrist tight.

I would want all of the same coils.

cpotts13

Don't mean to thread jack... but what do you recommend for spark plugs and coils?

Glenn

11 or 12 lbs I also think the coil either works or it doesn't work. So I would keep using the ones you have unless your throwing some code or have a bad missfire

mdelao

How can you realize that have a missfire?

cntchds

Everyone I have ever talked to about COP's says that you should always use stock Motorcrafts. Poisoned Pony put in an aftermarket set and they blew out really fast. Replaced them with stockers and that fixed the problems. They are pricey ($80 a pop) but they are the best quality COP's I have seen/experienced.

32vNomad

Also you want to replace the boots when doing the plugs. That can also cause missing type symptoms as well. Also use dilectric* grease in the boots before installing on plugs.

mdelao

Any recommended brand for boots?

pity7700

never use a torque wrench on spark plugs. alway wrist tight. use a normal socket wrench and spark plug socket. a torque wrench is a good way to over tighten the plug and break it.

its never a bad choice to go with OEM parts. Motorcraft COPs and plugs will work just fine. dont forget to put some dielctric grease on the top of the plug and some anti seize on the bottom of the plug where it screws into the head.

As for the COPs not having the hold down bolt on youll be ok. if you can try wedging something on top of it to hold it down. the bolts that screw into the COPs tend to break off if you dont clean the threads on them before screwing them back in. this happened on my truck, i ended up wedging a piece of heater hose between the COP and the fuel rail. i was getting water underneath it. you should be fine though, i doubt youre going to take your car through any kind of water or mud like me. the COP wont fly off.

Glenn

I'm going to have to strongly dissagree with you Chris. One persons wrist can tq more or less than the next guys wrist. When using a tq wrench your no more likely to break a plug than using a regular ratchet and socket. You have to be carefull either way or you can crack a plug. If you don't tighten the plugs enough they will work themselves loose and cause more problems than you want. My sources for the tq setting come from people like George Reid, Jim Grubbs and some of the guys at JGM performance.
Use a TQ wrench you can't go wrong!

As far as cop's go I agree with Peter using the motorcraft units. If you want to replace them buy and install one at a time if you have to.

pity7700

ive always been told not to use a torque wrench especially on something so sensitive. but you are right some people cant hand torque something as much as someone else. i guess if you have the proper torque setting set youll be ok but i still think hand torquing is much safer.

i guess everyone has their own ways of doing things. either way, if you use a torque or normal socket wrench dont muscle the plug. do it till its tight enough or at torque spec.

Glenn

My 2k gt is the first engine I ever used a tq wrench on, every other engine I just used the regular ratchet and socket for the plugs. My son changed the plugs in the engine the first time and one happened to come loose and actually popped out wrecking the threads and breaking the cop. That is was prompted me to use the tq wrench. Aluminum heads and all.

cdynaco

Doesn't hurt to check them after you've gone through a heat cycle or two because of the aluminum heads. As for me, I know the 'feel' of a tight plug.

32vNomad

Just remember they come from the factory torqued. Also so what you think is tight maybe over or under tight.

mdelao

The instructive in sparkplug box says that should be wrist thigh, and then like a 1/5 of turn. NGK iridium plugs

32vNomad

From the R&D team at Ford

303-07B-1 Engine Ignition -- 4.6L (2V) 303-07B-1
REMOVAL AND INSTALLATION
Spark Plugs
NOTICE: Do not remove the spark plugs when
the engine is hot or cold soaked. Spark plug
thread or cylinder head damage can occur. Make
sure the engine is warm (hand touch after
cooling down) prior to spark plug removal.

1. Remove the ignition coil-on-plug. For additional
information, refer to Ignition Coil-On-Plug in
this section.
2. NOTICE: Only use hand tools when
removing or installing the spark plugs or
damage can occur to the cylinder head or
spark plug.
NOTE: Use compressed air to remove any
foreign material from the spark plug well before
removing the spark plugs.
NOTE: If an original spark plug is used, make
sure it is installed in the same cylinder from
which it was taken. New spark plugs can be
used in any cylinder.
Remove the spark plugs.
o To install, tighten to 18 Nm (159 lb-in).
3. Inspect the spark plugs. Install new spark plugs
as necessary. For additional information, refer
Removal and Installation to Section 303-00.
4. To install, reverse the removal procedure
Copyright ã 2004, Ford Motor Company
Last updated: 8/10/2009