Understood. Will update following your original reply ASAP. thank you.

Here is what I have found:
Cylinder 4 had the least amount of change in idle when disabled.
Cam sensor retard below:
​​​​​​​​​​​​​​https://cimg0.ibsrv.net/gimg/blazerf...570913848f.jpg
​​​​​​​

Here is what I have found:
Cylinder 4 had the least amount of change in idle when disabled.
Cam sensor retard below:
​​​​​​​https://cimg3.ibsrv.net/gimg/blazerf...98446f438f.jpg

Cam sensor retard of 0° is right on the spec. But am curious why system is not in closed loop (you just happened to show this). Let's focus on that for a minute. Engine is running, correct? Not sure what cam sensor will read with KeyOnEngineOff.

If engine was running when you took the photo, double check the loop status with engine fully warmed up and running for a while - and if still open loop let's figure out why it isn't going into closed loop. This could be a key indicator for your performance issues since open loop only uses default settings programmed into the PCM at the factory and not any actual feedback from sensors. Also open loop could be mandated by the system not being able to meet some criterium required for allowing closed loop (like a failed sensor or circuit).

You do realize that this scanner is monitoring these parameters in real time? Just want to make sure you understand the difference between reading trouble codes stored in the PCM and reading real time PIDs (OBD2 Diagnostic Parameter IDs). The cylinder balance test utilizes what is known as bidirectional control (yet another mode).

As for the weak cylinder, I am asking for amount of rpm drop at both idle and at 2000 rpm when each injector is disabled. I am asking you to make two tables of data. And best if you can repeat by doing a second time.

Is the SES light working when you first turn the key on and then goes out when engine is started? Need to make sure this is the case.

So please report if engine was running or not when image was taken, and make the tables please. If engine was not running before, then also advise cam sensor retard with engine running. Also please answer question about SES light.

If engine was running when image was taken, and still is not going into closed loop when fully warmed up - then we will focus specifically on getting into closed loop in hopes this will lead us directly to the performance problem.

As an aside, for the KS counts - IIRC you said your 1998 has a 2001 engine in it. The knock sensor mounting is different between those years. We may need to see what the PO has done before we are finished (remember the EGR tube) but not a concern at the moment. What about the A.I.R. pump and associated tubing and valves going into the front of the exhaust manifolds. If that's not intact then that could possibly have something to do with the open loop since that quickly heats the O2 sensors when first starting. But eventually I would think that the system would go into closed loop, even without it working at all. Emissions readiness monitor would never pass but closed loop should still be attained eventually.

Yes, the vehicle was running but it wasn't up to temp. Checked again when it was at operating temp. Data below:
https://cimg3.ibsrv.net/gimg/blazerf...f1557824e.jpeg
Looks like it is going into closed loop, must've just not been to operating temp first time around.

Yes I do understand that it is live data, I appreciate you looking out for my understanding!

WITH that being said: when I initially started the vehicle a new code was thrown: P0135/$10 O2 Sensor Heater Circuit Bank 1 Sensor 1 (this sensor is a new Bosch sensor).

Yes the SES light is operating correctly.

DATA TABLES: (Data posted in order of which was disabled first to last)

2000 RPM Test 1:
1 1800
2 1850
3 2000
4 2000
5 2000
6 2000

6 1850
5 1850
4 2000
3 2000
2 2000
1 2000

1 1900
6 2050
2 2000
5 2000
3 2000
4 1850


Idle (700 rpms):
1 700
2 700
3 700
4 700
5 700
6 700

6 700
1 700
5 700
2 700
4 7000
3 700
As for your last statement: I'm not sure what the knock sensor mounting is but if I had to guess base on what I've seen done to this thing, it probably wasn't done correctly. Additionally: "A.I.R. pump and associated tubing and valves going into the front of the exhaust manifolds" I tried to take a look at this but I can't seem to tell exactly where to look to find this. If you could help me with any pictures/schematics to point me in the right direction, it'd be greatly appreciated.

Hopefully this information is more helpful/what you need, if not let me know and I can circle back. Thanks!

I was taking it for a test drive because after another visual inspection I noticed an exhaust manifold bolt wasn't fully tightened down. It seems that it was never tightened down because the EGR tube was blocking the ability to do so. I removed the obstructing side of the tube and tightened the bolt. I was hoping that this loose bolt was causing a bad air mix to B1S1 O2 sensor and had an effect but it seemed to have not. While I was on the drive I was watching my misfires: Cyl 1 & 4 had numerous misfires ranging anywhere from a couple to hundreds (I assume the counter was starting over?).

I'd also like to add that it would very much seem like the vehicle is quite sluggish. When at full throttle from low speed or dead stop it seems to struggle to get up to speed. It also seems to bog down when you rev it in park, not down so much as it almost stalls but some... I dont know if this helps at all but it's something I'd noticed and failed to mention... Possibly clogged cat...? Lastly, while at full throttle it makes a really terrible sound that's hard to describe. Can get video of it tomorrow...

I'm trying to understand your tables. for example"

2000 RPM Test 1:
1 1800
2 1850
3 2000
4 2000
5 2000
6 2000

Are you saying that you set/held the throttle at 2000 rpm and then disabled each injector one at at time, and this is the resulting RPMs during disabling of each injector? It would certainly make sense that your engine is running on more than 2 cylinders. We may need to get past this test and go on with an alternate. Something not right with this data. I think we can do things another way.

Is the PO135 setting with any consistency or was it just a single time?

CMP retard needs to be 0 +/- 2. We will fix this, but I'm not convinced it is the issue.

I'll see if I can snap some photos of the AIR system on mine. It is a 2001. Let me regroup and think about things a bit.

To clarify using the following table:
2000 RPM Test 1:
1 1800
2 1850
3 2000
4 2000
5 2000
6 2000
RPMs were help at 2000. Used the tool and turned off cyl 1 resulting RPMs were 1800 when disabled. Shut off cyl 2 resulting rpms were 1850. 3, 2000 and so on. Hope this helps.

so no drop for 3-6. Really dont think this is possible if the injectors are really being disabled. Like i said lets go on and not get stuck on that test with the ilink400. Not sure what is going on. Still thinking how to proceed.

At this point I really think we need to verify engine mechanical condition as described in post #2 by conducting both cranking and running compression tests exactly as described in the provided link. I know its a pain to do, but it needs to pass as the most basic requirement. Otherwise all bets for running correctly are off.