Cylinder 2 misfire mystery

Forgive me if this is a “dead” conversation. I know many people have posted about this and I hate to be yet another person kicking the cat with this . Let me explain, chastise me later lol. I’m dealing with an annoying idle with a cylinder two misfire involved. I’m at an absolute loss right now and it’s driving me crazy as I love my truck. I’ve checked all over the web to no avail describing my certain situation, unless my sleuth abilities suck. I’ll give as much detail as possible.

2004 Tacoma Crew Cab, 3.4 Ltr v6 - 5vz fe 233250 miles

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Issue: Cylinder 2 Misfire with rough idle under load or parked. Oil pressure light comes on during that time. No start or tough start when engine is warm.

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No coolant loss, smoke or excessive exhaust although it definitely smells rich. No milky oil, looks great.

Tried to relearn the idle, no change
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Parts replaced:
- Coil Packs
- Ignition wires
- Spark Plugs - all 6, correct ones
- Upper, Mid, Lower plenum gaskets
- Fuel injectors - all 6
- Throttle body gaskets with complete clean up
- Coolant temp sensor
- Engine knock sensors
- Fuel filter
- Valve cover gaskets with resealing half moon plugs
- Silicone vacuum lines throughout
- Radiator, hoses, thermostat.

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Cleaned out the entire intake manifold system, all three parts when I had it apart, they are shiny. Cleaned the throttle body top to bottom complete with new gaskets. New silicone vacuum hoses throughout the engine bay.

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Did the TPS tap trick to see if that was the issue to no avail. Ordered a new fuel pressure regulator as the oil has a gas smell to it, hoping that’s it since they can cause misfires etc. The fuel pump seems to be running good, no odd sounds from the fuel tank.

I’m at a complete loss at this point. I know there are a lot of smart people on this site who have the same love for their rigs as I do.

 

Double check all of your wiring, does it randomly occur? And if the code isnt present does the truck run normally?

 

All that money poured in, did you do a simple combustion leak and compression test?

 

This was my first thought something wrong either rings or valves . Now all these new added parts entered into the trouble shooting.

A simple tests that could have saved much time and money.

If all was good tossed the trouble shooting back to electrical it might be a simple open circuit

Has the oil pressure been checked through a manual gauge.

A poor ground back feeding into that circuit causing all the mischief.

 

Definitely appreciate all of the replies! I couldn’t agree more than there were a lot of parts put into the vehicle, believe me they were necessary, the vehicle wasn’t well taken care of minus oil changes. But all in all…..it’s my dream truck so maybe it’s a financial mistake or a labour of love lol

I did a compression test a while back but can’t locate the paper I wrote the info down on, will definitely get back to you all on that.

UPDATE:
Changed out the fuel pressure regulator and the cylinder two missfire has ceased to exist! Truck is idling like a beauty now but when I’m stopped at an intersection the low RPM idle comes back.

My thought is the fuel pump is going on it. I idle around 500 rpm but once I hit the gas everything runs perfectly.

 

Praying for you and family … New here just read your post