Not that it would cause fouling in one of your cylinders (at least in my opinion), I've heard nasty things about Bosch plugs. I have also heard from several different sources that the stock plugs (dual-ground NGKs or DENSOs?) will perform much better than any Bosch plugs will; even in supercharged or heavily-modified engines. As for the OBD code troubleshooting, I agree with John. Plus, compression tests are really easy. <img src="/forums/images/graemlins/kewl.gif" alt="" />

'99 Tacoma Xtra cab V6 TRD
TRD Supercharged, URD 7th injector and 2.2" pulley, 32X11.5 BFG All-Terrains, OME 881 3-inch lift/Toytec AAL, 5100 Series Bilsteins all around, and ProComp 130 lights.
No I'm not some creepy naked guy...