Spark plug Bosch or AC DELCO

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.

I use them. Just replaced a set after they'd lasted 90,000 miles, only to rule out a very very tiny misfire count issue I've noticed lately. I might get a coil pack now, but those original plugs surely would have lasted longer (they say they should last for 100k).

I just replaced my oem densos with some Bosch plugs that were labelled as being pregapped 1.1mm. I wanted them to be 1mm and checked with a gauge and Lo and behold they were already at 1mm. Whacked them in and improved my fuel consumption immediately.

I took it back in after setting the DPR to 2.5± 2.5 mA, checking again for any vacuum leaks, tightening down all the exhaust components, and changing out the spark plugs (again). I also checked the O2 sensor, it was fluctuating between .1v-.7v continuously.

So I went to my uncle who is a part owner of a auto parts supply company and he ordered me 5 Beck Arnley 178-8445 Direct Ignition Coils for my car and 5 ACDelco 41-806 Professional Platinum Spark plugs.

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.

My 6.0 never ran right unless I used AC Delco. And specifically whatever the current equivalent part number is to what the manual says.

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.