Misfire on cyl 3?

I would try switching a plug with #3 and see if it follows. Those look a bit ashy on the tips, along with a fair amount of soot. Have you cleaned the MAF? How is the air filter? Are there any codes in the memory for the turbocharger?

William

If that soot covered plug came out of 3 I would do a flow test on the injectors. For that you connect a fuel pressure gauge to the fuel system and a triggering device to the injectors. Then you pull the plugs out, run the pump to full pressure, watch the gauge, and hit the injector pulser. Record where the gauge started and where it stopped. If they all started at say 60 psi and 1, 2 and 4 all drop to 55 but 3 drops to 45 you found a bad injector. The pulser I use is one I built years ago (based off the OTC 3398) but there are a number of them available if you don't have one. If they all test OK then I would do a compression and a leak down test on the engine, soot like that is usually excess fuel but it could be blowby from a bad ring.

The easy way is to do a relative compression test and a cylinder contribution test, both require an oscilloscope. I LOVE my Pico scope, but there are others out there. As for the pulser, most simply have a switch and a button. The switch selects the amount of time the unit runs, the button it triggers the injector on, it pulses it for the selected time and shuts off. You then look at the amount of pressure the fuel system drops to tell if an injector has an issue. The image is similar to most of them. The cheap ones from the jungle river work just fine. However test the output, some pulse the positive side while others pulse the negative. You need to know what the one you have does if you want to use it in circuit. For instance on a vehicle where you cannot get to the injectors to unplug them, if they use a common power feed, you can usually find the negative control wire in the harness away from the injector and use a probe to put the pulsed signal from the tester in without any issues. In your case it looks like connector T8W might allow you access to the injector wiring without taking much apart.