Multiple misfires

Hi,

I looked at the pics you attached and noted a P0420. That is related to the catalytic converter. Is the misfire something that started all at once? I'm asking simply because I question if the catalytic converter may be partially plugged causing problems.

Also, keep in mind there are many things that can cause a misfire. Low compression, fuel pressure, vacuum leaks and so on. Is the scan tool you have provide live data? If it does, can you tell me what the short term fuel trims are?

Let me know. Also, here is a link that explains symptoms related to a bad catalytic converter. See if anything parallels what you have experienced before this started.

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms

Let me know.
Joe

Hi,

The trims seem high. Are you able to check fuel pressure? The computer is trying to remove fuel frim the mixture which, in this case with multiple misfires, may indicate a bad regulator and high pressure. Under normal conditions, they should range in the + or - 10%.

Let me know.
Joe

Hi,

Here are the directions specific to your vehicle for testing fuel pressure. The manufacturer's specs are listed in the directions. The attached pic shows location to attach fuel pressure gauge.

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2006 Honda Truck Pilot 4WD V6-3.5L
Component Tests and General Diagnostics
Vehicle Powertrain Management Fuel Delivery and Air Induction Fuel Pump Fuel Pressure Testing and Inspection Component Tests and General Diagnostics
COMPONENT TESTS AND GENERAL DIAGNOSTICS
Fuel Pressure Test

Special Tools Required
- Fuel pressure gauge 07406-004000B
- Fuel pressure gauge attachment set 07AAJ-S6MA150

1. Relieve the fuel pressure.

Pic 1

2. Disconnect the quick-connect fitting. Attach the fuel pressure gauge set and the fuel pressure gauge.
3. Start the engine, and let it idle.
- If the engine starts, go to step 5.
- If the engine does not start, go to step 4.

4. Check to see if the fuel pump is running: listen to the fuel filler port with the fuel fill cap removed. The fuel pump should run for 2 seconds when the ignition switch is first turned on.
- If the pump runs, go to step 5.
- If the pump does not run, do the fuel pump circuit troubleshooting.

5. Read the fuel pressure gauge. The pressure should be 390 - 440 kPa (4.0 - 4.5 kgf/sq. Cm, 57 - 64 psi).
- If the pressure is OK, the test is complete.
- If the pressure is out of specification, replace the fuel pressure regulator and the fuel filter, then recheck the fuel pressure.

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Let me know what you find.

Joe

That isn't good. Can you take a pic of what you have so I can see it? Also, they should have the connectors for both ends of the fuel supply and a T to join the gauge to them.

Let me know. Be careful. Make sure to protect your eyes and always cover connections with a shop towel to prevent the fuel from spraying.

Let me know.
Joe

Did it leak from the side that went to the engine? If so, check to make sure the o-ring in the connector isn't damaged or missing.

Let me know.
Joe

Hi,

Interesting there was no code for a misfire. Since the coil was bad, that is what was likely causing the STFT to indicate a rich mixture.

Regardless, I'm glad to hear it's fixed. Please feel free to come back anytime in the future.

Take care,
Joe