Bosch Spark Plug - 9621

We purchased these spark plugs for our 2015 Mazda CX-5, and they were fully compatible with the vehicle. Installation was straightforward and beginner-friendly, making it a manageable project even for those with limited automotive experience. Prior to replacing the spark plugs, our Mazda was experiencing noticeable hesitation and displaying a cylinder 1 misfire code. After installing this set, the issue was completely resolved, and the vehicle has been running smoothly ever since. The product met our expectations in terms of quality, performance, and overall value. One detail worth noting is that although the listing may suggest a single item, the package actually includes a complete set of four spark plugs, which was a pleasant surprise. I did not take photos of the new spark plugs, but I have included a picture of the worn-out plugs that were removed from the vehicle for reference. Overall, I would recommend this product to anyone looking for a reliable replacement. If engine issues persist after installation, it may indicate a different underlying mechanical problem rather than an issue with the spark plugs themselves.

Very good quality

Fit my 2009 Maxima.

Installed on 2009 Corolla. Gas mileage has improved by 2 mpg. You will need a 9/16" spark plug socket (https://www.amazon.com/gp/product/B004FEPFSY) for a 2009 - 2014 Corolla. The skirting around the top of the hood prevents you from using a single long extension to remove the old plugs. Instead, I had to use 2 small extensions, attaching the spark plug socket to one small extension, then adding another extension when the spark plug socket and first small extension were down in the cylinder. Because of the skirting around the hood and the fact that you have to use multiple small extensions, you cannot simply replace the plugs using the 9/16" plug socket. The extensions will separate in the cylinder before the plug socket comes free. Instead, use a piece of flexible tubing from a hardware store to reinstall the new spark plugs. The tubing you get should allow the white part of the plug to go up into the tube and not allow the plug to fall out when held vertically. You don't want to just drop the new plugs in the cylinders because the spark gap can be moved due to an impact with the bottom of the cylinder. Hope this helps!

Works for my 2019 Nissan Altima

Bought it for my Toyota Corolla 2009 LE and it fits well. I trust Bosch brand.

Replaced the OEM DENSO SC20HR11 SPARK PLUGS @ 100K mileage on my 2011 Toyota Corolla (2ZRFE engine). The engine performance improves greatly. Less idle vibration and better acceleration. The old OEM spark plugs look very burnt out. I'm glad I replaced them before they worn out, the Toyota service manual suggests the service due at 120k though.

I read other reviews of this item about the Chinese ones being bad and German ones being great. So I figured I'd order 4 and see, well I got 4 Chinese ones so I returned them, didn't bother trying them as I didn't want a potential safety hazard. Ordered them end of March 2020 in Illinois, USA maybe other locations have German ones not sure.

I placed an order for two Spark Plugs for AUDI A4 B5 however, I have received two spark plugs which one is larger and thinner than the other. I need either the order for the missing spark plug or a refund. I believe the the thin long one will not match the car. Please see the photo

Installed these on my Mazda 3 2014, and notice lower gas consumption and better, also better engine response at lower RPM

Perform as well as the OEM Denso plug, no problem at all. Hope will last as long as Denso ! Installed on a '09 - Corolla.

Just as described, work beautifully. For a 2009 Toyota Corolla

De muy buena calidad