Spark plug Bosch or BRISK

I went with [Brisk ER12s](https://www.fcpeuro.com/products/vw-spark-plug-brisk-racing-er12s) plugs. They are one of the plugs recommended by EQT and I have been happy with them so far. Cheaper than the NGK/Denso plugs but downside is that they are silver based, so they will wear out faster. I am at 10k miles on them now and starting to feel a little rough idle; time to re-gap or replace them.

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 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.

I’ve been running Brisks for 30k now and haven’t had any issues

Also, some engines get particular about plugs. Bosch has a bad rep for the 3400 engine in my Grand Am, while NGK and AC Delco(I've got NGK Iridium IXs in there now) are fine.

Took original plugs out at 50K miles. Not awful but electrode partially rounded with increased gaps. Stock plugs are Bosch and apparently copper core, so I replaced with same. Recommended gap is 0.043'' Added anti-sieze to threads for easier removal next time.

I then changed to a hotter plug the Bosch Platinum plugs and again gapped to .28. Once again the plugs fouled shortly after starting and driving for a few minutes.

Bosch finewires suck dong and AFAIK are not OE for anything even though they claim they're OE for practically every car on the road.

Bosch platinum are trash.