Also did spark plugs. My mileage dropped to 15.5 which is low for me even on winter blend. Fresh oil, fresh air cleaner, tire pressures all good so I figured it had to be plugs.
Checked the gaps on the NGK 6619 Iridiums. (Amazon - $58 for the set) They are all pregapped and all came out to .044 which is spec!
Pop the hood, disconnect battery and pull engine cover (it just lifts straight off)
Coil packs look easy to get to, but every single one had an obstruction of some sort. You will need a variety of extensions and will need to unclip and move things around.
Unbolt the coil pack (10mm nut) and unclip the connectors. I used needle nose pliers to make it easier.
After pulling the coil, I used some compressed air to clean out the tube before pulling the plugs. Use a spark plug socket with the rubber insert to help pull it out of the tube.
1st plug on drivers side out. The washers are captive on the plugs. Also, be sure to inspect the coil packs and rubber seals. Some of the plugs are really in there. You will feel like you unscrewed a 24" bolt on some of them.
Checked the gap. .0525. Could explain things. (all of the plugs gapped in this range)
Factory next to replacement
Dont forget your anti-seize before reinstalling. (Hand thread it first, then torque it) Repeat for rest of plugs. You will need to open the fuse box and slide up the wires to get to 1 of the plugs. Push the coil packs on hard and bolt the 10mm bolts back on. Make sure you get a positive click on the wire connectors as well.
Passengers side. Much more difficult. Pull the air cleaner and set to side. This lets you get to the front 3 plugs pretty easily.
Now, the firewall plug on the passenger side. Very hard to do. You have to unconnect the 3 heater hose brackets since they route directly over the plug.
10mm bolt, easy to undue. In between front 2 plugs.
12mm bolt at back of the head. Yeah, not easy. You have a very small degree of movement to get the hose out of the way to undue the bolt. You also need long needle nose pliers to unplug this clip. (top of the engine shot)
Heater hose bolt 12mm in very back of the head has to come out. About 14" of extensions and a swivel socket while trying to maneuver a wrench under the cowl.
See this really thick black wire bundle over the 2 silver tubes? Yup, the plug is under all of that and none of it wants to move.
So my tips. - Take your time, you will need to maneuver, twist and turn to get some of the coil packs out.
If you drop a socket/tool and it doesnt hit the deck, you will likely need to pull a skid plate to get to it. (I used a long mechanics magnet for the 1 socket I dropped.)
So all done. Double check your connections, make sure all of your tools are picked up, reconnect battery and start her up.
All the tools needed. Job took 3 hours with most of it on the last plug. Dealer quoted @ $350 for the job (parts and labor)
So here is where I was after last fill up. Lets see if this helps get those mpg's back up.
