Never worked with bluedriver before. I bought a cheapy Chinese ELM327 OBD2 module off eBay, think I paid like 12 bucks for it. Paired with torque pro, it gives you the ability to view live data from your running engine. Not sure if bluedriver can do that as well, I would guess it can. You want to know what your long term fuel trims are (ltft1 ltft2), short term trims (stft1 stft2) and also your o2 sensor voltages. This will help narrow down the issue. I would think if the plugs were a problem, you would get a code all the time. With fuel trims, you can be out a little bit or a lot, but the obd won't throw a code unless any of them is +-30%. So you could have a ltft1 reading of +25%, ltft2 of +12%, be running like shite, and still not get a code. Sure, you could just throw parts at it, but if you're in the dark about what's going on, that could get expensive quick, fast, and in a hurry.