why are you changing it? how many miles do you have?
+10000000000000 Do them one at a time and follow the above advice. Its super easy to do.The only thing I would add would be to direct a compressed air blast into each spark plug hole after removal of the coil packs and before removing the spark plugs. This will ensure that if any loose object has fallen into the spark plug tube it will be expelled and not fall into the cylinder when the spark plug is removed. Also plug each tube opening with a clean rag if you do not put the new plug in right away. There is nothing worse than dropping a tool like a small socket or a small nut or washer only to see it fall into a spark plug tube and into the cylinder. The only way to get someting out of the cylinder is to pull the cylinder head and that is not something you want to do.
Peopl have mentioned the gaps on the spark plugs... is this a real issue? Should I be aware of any particular gap issues?It's very easy and will only take a few minutes. See pages IG-1 through IG-7 (pg 270-276) of the Celica Repair Manual, Vol 2. Snippets below:
View attachment 129843
Next, use a 16 mm (0.63 in.) plug wrench, remove /install the spark plugs. Torque: 18 N m (184 kgf-cm, 13 ft-lbf)
The Celica Manual recommends these spark plugs:
DENSO made, SK20R11
NGK made, IFR6A11
But, you might look around both here and newcelica.org to see what people are using these days.
Does it help? Yes. Will you notice any difference? No. Maybe if you were running a 1,5000 HP top fuel dragster, but for a normal (or even high performance) street car, it will be unnoticible.Also, plugs on most cars can be indexed, so the gap faces the intake valve. You need to mark the socket and try various plugs to do this. I have no idea if it helps for real...
Wait....my Elise DOESN'T have 1500HP????Does it help? Yes. Will you notice any difference? No. Maybe if you were running a 1,5000 HP top fuel dragster, but for a normal (or even high performance) street car, it will be unnoticible.
I've been known to mark the plugs and swap them around so that I get the most "indexed" combination, but never to the extent that I would swap other plugs for a larger selection (i.e. I only have four plugs - I make the most out of the four, while still understanding that it isn't going to make a difference...).