Spark plug Bosch or NGK

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.

For spark plugs I always used NGK because that's what Motorcraft actually uses if I remember correctly. Autolites are complete garbage and always fouled out the few times I used them.

You can honestly just run stock plugs on the 1.8 with OTS tuning for stage 1/IS20/38. I ran these same VW/NGK "RS7" plugs including track use for thousands of trouble free miles.

To be honest the last plug VW went with , the 101905601F (OEM clones Bosch copper nickel FR7HE02 Or NGK ZFR6T-11G (5960) Copper Nickel, Beru BRU-Z272 copper nickel ) for the 2.5 is best. It’s one shade cooler and will have less spark knock. You have more timing.

I forgot to mention that I installed brand new pre-gapped NGK spark plugs two years ago

I like NGK, but you can't go wrong using what the manual calls for.

Champion and NGK have good reputations.

Bought mine from rock auto; got the Bosch ones since the NGK’s are really only recommended if your car is tuned

Do not I repeat do not put Bosch plugs in any import. Don't know why but they always cause problems.

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.