Spark plug Bosch or OEM Honda

I recently changed my spark plugs on 2012 Ford Focus. I used Bosch and got a 3 MPG boost.

Since I mounted Bosch 4-prong spark plugs, fuel economy has improved a lot. Gone from 12-13 km/l to nearly 15 km/l.

I have only used Bosch plugs in my cars, and I have not had any issues with them yet.

Bosch iridiums, these for longevity, copper ones have better spark if your concern is performance

Today I installed new spark plugs and the misfiring situation has improved significantly but is not completely gone. If I pull up the RPM too quickly the misfire counter goes up.

Just got a Jetta again - 2010 Limited Edition just shy of 100K miles and I've got one problem with it. From a cold start, usually in the morning, the 1st 10-15 seconds run rough before settling down to idle.

I have never seen any real large difference in NGK, Denso, and Champion if the proper heat range/type plug was used.

I'm not a fan of the old platinum Bosch design or regular autolite.

Ive used bosch irridium plugs as replacement for the original denso ones in my GFs 2015 yaris and the car started to have misfires (noticable shuddering) within a couple of weeks. The bosch part is listed as compatible with the OE number, but issues nonetheless. I'm currently going through the warranty process and definately wont be using anything other than the direct denso replacement.

Yeah I own and operate an auto repair facility and refuse to use Bosch plugs because I’ve had a lot of issues with them in the past. Misfires mostly.

I've heard for many decades how bad Bosch spark plugs are and I figured the coils would be just as bad, if not worse.