The Dreded Random Cylinder Misfire

[Dom2door]

Trying to troubleshoot a misfire.
It started when a slow driver moved out of my way, I gave it gas what down a gear then things went wrong.
Spurring, piping, rough idle and light on dash flickering.
Things I tested.
Fuel pressure, 50 psi at idle, 55 not running and holds pressure with key off.
Timing CMP looks ok (see photo) RPM @ 2000
Fuel trims questionable (see photo)

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I would hate to start throwing parts at it. I pulled the distributor cap and it had some white crusty stuff in some of the pins, replacing cap and rotors.
THANK you for any help.

 

[stutaeng]

Both banks ran lean on that graph? Can you get same graph with RPM on the horizontal scale?

Edit: I now see what the guages are on the lower photo. Lot of mis-fires on 2 & 4 cylinders...!

 

[Schurkey]

WHAT ENGINE? WHAT VEHICLE?

#2 & #4 are misfiring. Both are on Bank 2. Misfires drive the oxygen sensor to report false "Lean" signals to the computer.

Computer responds by enrichening the mixture. Bank 2 fuel trims show major amounts of fuel enrichment. (3 times the amount of enrichment compared to Bank 1, which has only minor misfire.)

Figure out why #2 and #4 are misfiring, the fuel trims may fix themselves.

Spurring, piping, rough idle and light on dash flickering.

I have NO idea what "spurring" or "piping" are. WHICH light on the dash is flickering? WHEN does it flicker? Do you mean "flicker" or do you mean full-brightness, full-off flashing at regular intervals?

If the MIL is flashing, it's telling you that the catalytic converter is in danger of meltdown. Common, when the computer detects misfire.

I pulled the distributor cap and it had some white crusty stuff in some of the pins, replacing cap and rotors.

Corrosion on SOME of the terminals? Not all eight?

I'd be looking at the plug wire resistance, and the spark plugs.

How old are the spark plugs? Plug wires? What is the cranking compression of 2 and 4, compared to any cylinder that isn't misfiring?

 

[Dom2door]

I have NO idea what "spurring" or "piping"
That was supposed to be sputtering and popping, spell check.

Check engine light was flickering, I did smell the the cats where getting hot.

I still need to check the spark plugs and do a compression test on the cylinders, I will do that once I get a compression tester.

1999 2dr Tahoe 5.7

Plugs, wires cap and rotor are about 3 years old.

The new cap and rotor fixed it.