Original plugs: NGK LFR6C11 V-power traditional plugs (left bank) and Denso K20HR-U11 (right bank)
- Fuel economy on old plugs: 16mpg during mixed spirited driving, 18mpg max during conservative driving (avg)
New plugs: Denso SK20HR11 extra long-life Iridium (0.7mm iridium tip) plugs with flat platinum ground and copper core
- The OEM 2GR-FE spark plug is better: FK20HR11, double tipped (0.5mm iridium electrode tip, 0.7mm platinum ground electrode tip)
- Fuel economy on new plugs: (avg)
Tools: 10mm socket, 16mm spark plug socket, various extensions, torque wrench set at 19ft-lbs
Notes on the old plugs: Wear was pretty typical for a traditional plug. The NGK's have less electrode than the Densos. I guess they are designed that way since NGK puts a cut in it. There were no obvious signs of excessive wear, running rich, or lean on the plugs. My engine had both Denso and NGK spark plugs in it.
The tuneup took roughly 45 minutes and some patience. It also took a couple of long extensions to avoid hitting emissions stuff. The left bank was the more difficult bank to do, so I did that one first. That one took about 30 minutes. I used a small flathead screwdriver to pop the tabs up on the COP (coil on plug) connector. There wasn't enough space for me to squeeze the tab, so it was just easier this way. I then used a 16mm (or 5/8ths) spark plug socket to remove the plugs. I did have to disconnect the PCV hose and move it out of the way temporarily. The spring clamp didn't have too much tension so you can squeeze it with your fingers and pull the hose off. Two other hoses on clamps had to be moved near the 2nd cylinder. I just popped them out of their holder clamp and moved them as needed. The right bank was ridiculously easy. Just remove the air filter and holder, and you have complete access to all of the plugs.
With the new plugs, the engine seems to idle a bit smoother, and power is good as always. Can't really say too much on them since I've only driven 300 miles since the tuneup. I'm trying to determine if there's a significant fuel economy improvement using real empirical data. I've never broken 20mpg on my truck. Here's to hoping.