Possible fuel issue?

[L8RH8R]

Bit of an update. Exhaust is complete. Noticed the scan tool indicated the O2 sensors were not sending a signal. I removed the O2 sensors to clean them up a little. Heavy carbon. After I reinstalled them and ran the truck, it was a little better. I took a closer Look and noticed the ones I had (tip was rounded with what appeared were small slots in the tip) were different than the more squared off tips which have small holes in them. I purchased ac deco O2 sensors (more squared tip) and installed them. Truck ran much better. I still have the multiple engine misfire code, knock sensor one low voltage and 0650 mil. I also now hear a distinct ticking noise (electrical) noise coming from the coil injector area. Also, truck is very sluggish when I drive it. Most likely due to the Aforementioed codes. Thanks to everyone who has responded. Gonna keep looking.

[L8RH8R]

So even more of an update. The previously codes remain. I have ordered ac delco knock sensors and I will check the intake for warpage and possible leaks when I replace the sensors. What I found really interesting was this; as I checked the fuel injector wires with the noid light, I came to injector 5. If you remember, I mentioned hearing a ticking noise on the drivers side of the engine. I checked injector 5 and as i removed the actual plug from the injector, the ticking noise stopped. Once the injector was reconnected, the noise started again. The noid light did function on 5. My guess is either an injector that's not working at all or dumping fuel. I'm guessing the latter. Any input is appreciated.

[L8RH8R]

While waiting on the knock sensors to arrive, I decided to swap out the #5 fuel injector, the one I thought was making the noise. After swapping in an old injector I had, the noise continued. I then unplugged the #5 coil and the noise stopped. Just like when I disconnected number 5 injector. I swapped the coil pack with number 1 and the noise continued in number 5. Whether I disconnect the injector or the coil on number 5 the noise stops. My hope is replacing the knock sensors and resealing the intake gasket takes care of the multiple engine misfire. What gives? Any help is always welcomed

[L8RH8R]

Not much of an update, still having an issue. Discovered that there was a small intake leak at the IAC sensor. A little permatex later and problem solved. However, the rich smell remains. The scan tool indicates the 02 sensors are both flatlining (no function) at 450mv. The PCM still says its in open loop and the fuel trims are disabled. The truck drives ok at times and others not so much. Consistently inconsistent. The hard start remains and on occasion there is a backfire through the intake. Any help is greatly appreciated. Pulling my hair out.

[L8RH8R]

Major breakthrough. First, the hard start issue. A friend of my nephews came over with his Power Probe (a must have) and probed the ignition wire as I attempted to start the truck, significant voltage drop. We moved the wire to another 12v source that did not have any voltage drop and viola, SUCCESS. The truck cranks right up. On to the O2 sensors not working correctly. We checked the wires both in the main harness and O2 sensor harness and all was good. When back probing the PCM O2 wires, nothing. He asked to see the old O2 sensors I had in place before the AC Delco units currently being used. He discovered what I already knew. The old O2 sensor plug was 180 opposite the AC Delco units. He explained what each wire did and hypothesized that when the old O2 sensors were in place, it was possible a 12v signal was sent to a capacitor/resistor in the PCM that was not designed to have 12v thus damaging it. I contacted the company, Affordable Fuel Injection (those guys are great), who asked me to send them my PCM and one of the O2 sensors to check the function. I'll update sometime next week hopefully. Happy Thanksgiving.