⚡ NGK IZTR5B11 Laser Iridium Spark Plug, Pack of 1 - Improved SEO Review

I've had them for 11 months. Works well, even noticed a 1-2mpg increase in gas mileage. I connected them to a Taylor Cable 82644 ThunderVolt. Will buy them again if I need to replace them.

, better fuel economy, more power and less idling on the piston. This is called spark plug indexing. That's why the dealership setup costs $145 for a '95 Silverado or $245 for an '09 Corvette.

I bought these for my 2004 Chevy Avalanche Z66 with 202,000 miles. I changed spark plugs and cables. For wires I used ACDelco 978HH. It seems like forever, I get 15.5mpg. Today I got my first tank down to 1/4 tank. I filled up again and checked my mileage. Unbelievable, I got 18.7 mpg. I am impressed. I hope this continues. I'll probably make this an annual routine.

Replaced factory spark plugs on Chevrolet Silverado 2008 (5.3L). They work perfectly and the car runs like new. DO NOT CHANGE THE SPACING ON THIS PLUG. Other reviewers have noted this, but it's worth repeating. They come from the factory correctly spaced for these plugs, although it doesn't hurt to double-check. All mine have been adjusted to manufacturer specs, I haven't altered them at all and they work great.

I was a bit rushed to order these spark plugs from Revain as some third party suppliers charge you a 20% restocking fee if you need to return them. Revain's auto parts claims aren't that accurate, and then you could get burned if you have to return them. However, I was able to verify that these connectors would fit my Silverado SS by looking for the correct part number at several auto parts stores. They are installed and work great.

I ordered these plugs after reading articles on the GM truck forum. The previous reviewer is correct that they come with a .040 clearance and the factory clearance is .060. After reading the truck forums it states that due to the design of the plugs they need to be installed as is with a 0.040 gap. After installing it, I didn't notice much of a difference until I went on my usual weekly commute. On a freeway trip, my truck (2005 GMC 5.3) was looking for a transmission while going up a steep…