I am about to embark on a journey to change Spark plugs, on a '98 4.6L. Hoping to get rid of a P0304 code. Been inconsistantly getting worse, started back in August of '07, but finally threw a code Tuesday coming home from work.

Any tricks I need to know about?? I hear that #4, the one giving me a code, can be a PITA. What is easiest way to change it. Are the rest of them pretty straight forward?

I'll be changing both coils, all 8 plugs, and all 8 plug wires. Ordered the troyer performance ignition upgrade. Figured it would rule out the entire igintion system. Will also be changing all filters, oil, etc. Any other advise on getting rid of this code is appreciated.

 

First time can be tough! Use a loop of string around the top of the plug cap and pull in line with the plug. I use 3 3" extension plus a 6" and a plug socket with insert to remove the plugs. Tape the socket and a 3" extension together as its tough to remove the socket from deep in the plug hole. Engine should be cool to. Should take about 2 hours first time for plugs. Take photos for wire runs and make a note of which wire from the coils goes to which plug.

 

if you try to gap the densos be extra carefull as the head is so small.
i brought the troyer kit and love it.
also i disconected and replaced one plug at a time so the wires all lined up properly.
oh and dont forget plenty of canned air to get that crud out of the holes before removing the plugs.

 

Start on the driver side. (not a have to thing, but, you get the worse over with first.) Make sure you use dielectric grease.

And, all of the above posted advise will keep your blood pressure down. LMAO

Good Luck!

 

i like to use 2 sockets. the plug style with a rubber in it to pull the plug and to "lightly" reinsert the new one. i put my plugs into the rubber gripper just deep enough the plug wont fall but i can hand tighten it a thread or 2 to keep it from falling over then use the regular socket.

 

I too plan on doing one plug at a time. Unhook stock coil, and mount new in place. As I go, remove plug wires and plugs one at a time. Leaving them mounted to the original coils for reference, should I run into a problem. I will take pics as well, to ensure correct hook up.

Is air compressor air not enough?? Do you really need canned air, or is it that you can't get into the tight area??

I will double check the gapping, I looked at one today, and thought to myself, Man I hope I don't have to regap those things. That nipple is TINY!

Going to parts store in a few minutes to get dielectric grease, and anti-seize for plug threads.

I have a ton of different length extensions, one is nearly 2 foot. But why some many 3"?? I suppose it will become clear when I finally dive into it. Taping the socket to the extension is a good Idea, will do that.

I wish these were a little more convensional type heads, with spark plugs near exhaust, but it does not look like there is much room there either. But at least you could see the plugs.


Thanks all for the advise. I'll let you all know how it goes. Will be wrenching Saturday (tomorrow) afternoon. Will also be changing Air, Fuel, and Oil filters along with oil of course, at the same time. I am hoping all of this will net me some better MPG, and a smoother running truck.

 

You don't want anti-seize on the 98 plugs - trust me

 

I never changed plugs on these new engines but on the 351 there were a couple that was hard for my to do. I would take a gardon hose about 8-10 inches long stick the new plug in the hose and with little effert it was in.

 

thanks for the Heads up JBrew. Is it the later heads that need the Antiseize? Keep in mind this a 4.6 not 5.4. I thought the 5.4's had the plug problem?

Also I do not have a in/lb torque wrench. and am unsure if the one I have will go low enough. How tight is tight enough? Finger tight, then 1/4 - 1/2 turn with wrench? I don't want to strip these threads, but I don't want the damn things comeing back out either.

Thanks again for the advise.

 

No Problem -

Not a 5.4 specific problem . A certain amount of 5.4L heads were over torqued at the factory at one time . But being that the 4six and 5four share the same heads , the problem eventually surfaced with the 4six . I've seen more 4six blowouts on this site than 5four's since I joined.

3 and 4 loosened on me with anti seize. These plugs don't need any help coming out

The best trick is threading the new plugs in with a piece of 3/8 hose . Torque should be between 12-16 foot lbs.- I never use a torque wrench on the plugs myself.

The 2004 + models , now that's a different story..

 

sad thing is, NGK plugs have a torque diagram on the back of the box. i think it said for aluminum head finger tight then 1/2 - 2/3 turn.

 

So, then a 1/2 turn extra is correct? I am using Denso's but doubt torque settings are any different.

 

Nice Plugs - They work well in these motors.



Just don't reef them down - it helps knowing what 16' lbs feels like , it should be half to 3/4 turn MAX - go by feel.

And grease the insides of the boots well - I would even silicon seal the plug wires. You'll want to contain all that spark.

 

That would be the plugs i'll be installing. Nice ot know I got help should I need it. Waiting until noon, for the warmth. Can't use Garage, as the Galaxie inside has no brakes. UFF another project I need to finish.

 

Galaxie -a 500? Didn't they drill out the frame at the factory for lightness -oh wait, that was the Impala I think . Oh well , nice car..