Spark Plug Install Instructions

They are usually really close right out of the box, but you can gap the plugs you just have to be really careful and not put any stress on the iridium tip. Run a gap between .026" to 0.28".

Cool, I can't wait to get this done.

Mine are all gapped at .32

That's ok, but I really would prefer to see them gapped to 0.026-0.028. Again. be careful checking the gap and setting the gap. Do not put any stress against the iridium tip. If you do, they can break off and the plug will be fubar.

Chad (jdmchizad) is just getting to the point where he can put the new plugs in. I can never remember the proper way to downsize the gap. Anyone? My way of smushing a DSM plug on the work bench may not be the best for these delicate little things.

Tapping it lightly against a wooden work bench is actually a good way to close the gap down a bit. You don't need a lot of force, a few little taps is about all it should need. Go a little at a time.

He made pretty short work of it, considering this was the first time on the Legacy. He's still out there putting his maps back on, etc.

And... I definitely recommend the "turn it 180 degrees" idea on the rear driver side coil pack. It hardly took any time at all after reading that hint.

Just me $.02 (and I told a lot I dont know WTF im talking about) I would get the missfire fixed before I went introducing new issues into the mix.

This would be one of those times. If there is one thing I've learned from my ever problematic DSM, it's that when there is a misfire, go after the most common cause first... plugs and wires. Compared to determining an injector failure, fuel rail clog, bad coil pack, or other potential problems, plugs are easy. This is fixing the misfire... and if by some slim chance it turns out that it isn't stemming from the plugs, I will definitely let you know.

This would be one of those times. If there is one thing I've learned from my ever problematic DSM, it's that when there is a misfire, go after the most common cause first... plugs and wires. Compared to determining an injector failure, fuel rail clog, bad coil pack, or other potential problems, plugs are easy. This is fixing the misfire... and if by some slim chance it turns out that it isn't stemming from the plugs, I will definitely let you know.

Im not disagreeing i'm saying that going for 1 step colder is adding another variable not taking 1 away

And 1 step colder isn't that big of a step anyways. 2 to 3 steps colder would be a considerable issue.

Car still runs killer... Can't wait to track it this Sunday!

I just replaced the plugs on my LGT at nearly 37k miles. The originals looked good with a slight hint of a lean burn.

The driver's side rear coil pack posed no problem with removal. On the other hand, reinstalling it was a pain.

I had the dealer change my plugs as I was incredibly short on time. Could they have put platnum in instead of iridium? They said they were OEM plugs. Their "service sign" said platnum on it but I assume that's simply because other models (older models?) take platnum, not iridium.

Thanks for the write up. Definitely will do them myself next time.

^ Did you unplug the battery?

If so, you're probably just getting a bit of harder-than-usual "pushing" from the ECU, which is typical after a "ECU reset."

^ Did you unplug the battery?

 

If so, you're probably just getting a bit of harder-than-usual "pushing" from the ECU, which is typical after a "ECU reset."

yeah, probably. i reloaded my stg 2 realtime map also which contributed to it.

Drivers side:

 

The front coil is a piece of cake and is just as easy as the passanger side front. However, the driver side rear is a headache. The space is tight and the problem is not getting the 12mm bolts off, which is the same as the passanger side. The rear coil pack does not have alot of slack to it interms of the wires running to it. Ontop of that, it is extremely close to the fender wall and takes some work to get out (Pic 1). The previous three coil packs you are able to take out and draw them up. However, the driverside rear you have to place below the cylinder because it is too tight to pull it up.

There is a better way to remove the rear drivers side coilpack. Fist you unclip that black padding next to the coil pack. 2nd, unplug the black connector on the coil pack. Finally you can easily remove the coil pack from the top easier than the bottom by rotating the coil pack.