What are the hottest spark plugs realistically usable in a 328? (Gridlock special) The plugs that worked in Boston traffic seem to be getting a bit fouled by sitting at the out-to-lunch traffic lights in the Arlingrad area. (The car runs okay, but idles rough, and now is getting a bit of hesitation leaving idle. I haven't pulled the plugs to check, as I'm driving it every day, in our nice weather. But where more driving usually makes it run better, now it's getting a bit worse, from the daily commute through crawl hour.)
I can't recall a single report here of a 328 fouling plugs, so you might have something else (bad) going on injection-wise if you are fouling plugs (i.e., a US version 328 shouldn't run rich, even at "crawl", since it has O2 sensor feedback -- and 328 have a decent electronic ignition). Is your 328 a US or Euro version? In additon to heat range, you might also consider trying the fine-wire center electrode technology that is more resistant to fouling -- i.e., a set of NGK DR7EIX (which is the Iridium style NGK 1 heat range hotter than the stock "8").
Ditto --- With the 328, if all the systems are working correctly and in spec, you shouldn't be fouling plugs in any driving conditions. I suggest pulling all your plugs and examining the deposits to determine whether the problem is over-rich fuel mixture or oil contamination. On the injected 308's / 328's, it's never been recommended to exceed a heat range of 7 for any plug you chose to run... Also, I've had better results as well with NGK wire type tips on higher mileage cars which suffer from mild oil fouling due to leaking valve guides, rings, etc. These tips will stay cleaner longer than the other configurations.
