Engine Vibration + Misfire CEL (P0301, P0316). What vibration is normal?

I recently had the Ranger pop a CEL P0301 and P0316 (cylinder 1 misfire) and the engine was vibrating badly with a loss of power.

In my diagnosis, I first checked cylinder 1 compression and it was normal. I then used a crowbar to "listen" to my fuel injectors and the cylinder 1 injector seems to function and sound the same as the others. Visually, the engine mounts look fine.

Lastly, I pulled the spark plug from cylinder 1 and 2, cleaned and re-gapped them, then put them in swapped locations. I also swapped the wires from 1 and 2, the theory being that the code would show cylinder 2 misfire if it was a bad plug/wire. I started it up, cleared the OBD code, and to my surprise the bad vibration was gone and no more CEL even after a day of driving. So maybe it was just a dirty plug/bad connection.

HOWEVER, when I pop the hood, it still seems like the engine is vibrating more than before the CEL. From within the cabin, the vibration isn't noticeable unless you stop and really concentrate on it. How much vibration is normal on the 3.0?

Is it possible for the cylinders to be misfiring but NOT pop a CEL? Is there even such thing as a "less severe" misfire? I'm going to order new OEM plugs and wires, not sure if I should replace the coilpack too? Or maybe I'm just overreacting and a little bit of vibration on the 3.0 is normal?

Look forward to your thoughts!

What year is this Ranger?
1994 model year would have 3 digit codes not 4, PXXX was 1995 and up with the new OBD2 computer

1995 and up misfires are detected by the computer timing the CKP(crank position) sensor teeth, 35 teeth 10degrees apart, a misfire will not add power to the crank so it slows slightly.
Computer also monitors feedback from the coil pack to see if and when spark plugs fired.

Misfire codes are not set at the time of the one event however, it has to be repeated within a certain RPM range over and over to set a specific, P0301 to P0306 cylinder code.
Random misfire is detected the same way but computer can't ID specific cylinder, and it also takes time to set this code.

If you get a Flashing CEL that would be a hard or complete reoccurring misfire, which can cause engine damage so the CEL Flashes the warning instantly during the event.
i.e. if you were accelerating and got flashing CEL then let off the gas and flashing stopped

The "soft" misfire codes can come back given some time.

Vibration is relative, but there should be none, engine is balanced so any vibration means there is an unbalance happening, which can be misfires or "underfires".
If a cylinder fires but doesn't generate the same downward force on the piston(power) as the other cylinders then cylinder underfires and less power is added to the crank so crank doesn't pick up as much speed as computer expects it to, this would cause engine vibration.

Could simply be dirty injector tips, especially at idle, the tips cause fuel to spray out for a better mix with the air, when they get dirty they drip fuel out so a less "powerful" air:fuel mix.
Put a can of Seafoam in the gas tank to clean injector tips.
I do this once a year in my '94 4.0l, really helps smooth out the idle which can get rough toward the end of the 12 months, should probably do every 6 months but I am cheap

If you have a 2004-2006 3.0l Ranger then P0301 with P0316 can mean exhaust valve seats are getting recessed, heads need to be replaced or new seats installed in the old ones

RonD said:

What year is this Ranger?
...
If you have a 2004-2006 3.0l Ranger then P0301 with P0316 can mean exhaust valve seats are getting recessed, heads need to be replaced or new seats installed in the old ones

Click to expand...

Thanks for the detailed reply!

Forgot to mention that this is a 2008 Ranger with 180,000 kms.

I already did a compression check and that was ok, so hopefully that means the head/valves are ok.

Good point on the fuel injectors, I'll put some Gumout Regane Complete in the tank and see how that goes. I'll also try replacing the wires and plugs to see if that helps. Last resort will be the coil pack which is $$$.

2008 3.0l had no exhaust valve seat issues.

Fuel system cleaner always helps my idle.

Ok so I swapped in a new coil pack and the minor vibration is still there. I tried using my phone's Torque app to pull Mode $06 data to see if I could catch any misfires in real time but it doesn't seem to be pulling in the misfire data correctly.

I'm really stumped now, anyone have any ideas?

Here's the report:

Mode $06 report generated by Torque for Android
================================================

Vehicle VIN: Not present
Vehicle Manufacturer: Unknown
Vehicle Calibration ID: Not present

Test report:
------------------
MID:$01 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 1 Sensor 1
Max: 7.99527V Min: 0V
Test result value: 0.45018V
PASS
----
MID:$01 TID:$80
- O2 Bank 1 Sensor 1
Max: 7.99527V Min: 0.49996V
Test result value: 0.76018V
PASS
----
MID:$01 TID:$81
- O2 Bank 1 Sensor 1
Max: 3A Min: 0.23A
Test result value: 0.502A
PASS
----
MID:$02 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 1 Sensor 2
Max: 7.99527V Min: 0V
Test result value: 0.44994V
PASS
----
MID:$02 TID:$81
- O2 Bank 1 Sensor 2
Max: 3A Min: 0.22A
Test result value: 0.92A
PASS
----
MID:$02 TID:$82
- O2 Bank 1 Sensor 2
Max: 6,553.5mV/ms Min: 0mV/ms
Test result value: 0mV/ms
PASS
----
MID:$02 TID:$83
- O2 Bank 1 Sensor 2
Max: 6,553.5mV/ms Min: 0mV/ms
Test result value: 0mV/ms
PASS
----
MID:$05 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 2 Sensor 1
Max: 7.99527V Min: 0V
Test result value: 0.45018V
PASS
----
MID:$05 TID:$80
- O2 Bank 2 Sensor 1
Max: 7.99527V Min: 0.49996V
Test result value: 0.74615V
PASS
----
MID:$05 TID:$81
- O2 Bank 2 Sensor 1
Max: 3A Min: 0.23A
Test result value: 0.561A
PASS
----
MID:$06 TID:$01
Rich to Lean sensor threshold voltage(constant) - O2 Bank 2 Sensor 2
Max: 7.99527V Min: 0V
Test result value: 0.44994V
PASS
----
MID:$06 TID:$81
- O2 Bank 2 Sensor 2
Max: 3A Min: 0.22A
Test result value: 0.934A
PASS
----
MID:$06 TID:$82
- O2 Bank 2 Sensor 2
Max: 6,553.5mV/ms Min: 0mV/ms
Test result value: 0mV/ms
PASS
----
MID:$06 TID:$83
- O2 Bank 2 Sensor 2
Max: 6,553.5mV/ms Min: 0mV/ms
Test result value: 0mV/ms
PASS
----
MID:$21 TID:$80
- Catalyst Monitor Bank 1
Max: 0.49999Ratio Min: 0Ratio
Test result value: 0.07422Ratio
PASS
----
MID:$22 TID:$80
- Catalyst Monitor Bank 2
Max: 0.59765Ratio Min: 0Ratio
Test result value: 0.03516Ratio
PASS
----
MID:$31 TID:$80
- EGR Monitor Bank 1
Max: 32.767kPa Min: -1.743kPa
Test result value: -0.017kPa
PASS
----
MID:$31 TID:$81
- EGR Monitor Bank 1
Max: 1.743kPa Min: -32.768kPa
Test result value: -0.017kPa
PASS
----
MID:$31 TID:$84
- EGR Monitor Bank 1
Max: 4.054kPa Min: -32.768kPa
Test result value: -0.185kPa
PASS
----
MID:$31 TID:$85
- EGR Monitor Bank 1
Max: 32.767kPa Min: 1.494kPa
Test result value: 6.493kPa
PASS
----
MID:$3a TID:$80
- EVAP Monitor (cap off)
Test incomplete or dependant test failed
--
MID:$3a TID:$81
- EVAP Monitor (cap off)
Test incomplete or dependant test failed
--
MID:$3a TID:$82
- EVAP Monitor (cap off)
Test incomplete or dependant test failed
--
MID:$3b TID:$80
- EVAP Monitor (0.090")
Test incomplete or dependant test failed
--
MID:$a1 TID:$80
- Misfire Monitor General Data
Test incomplete or dependant test failed
--
MID:$a1 TID:$81
- Misfire Monitor General Data
Test incomplete or dependant test failed
--
MID:$a1 TID:$82
- Misfire Monitor General Data
Test incomplete or dependant test failed
--
MID:$a1 TID:$83
- Misfire Monitor General Data
Test incomplete or dependant test failed
--
MID:$a1 TID:$84
- Misfire Monitor General Data
Test incomplete or dependant test failed
--
MID:$a2 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 1 Data
Test incomplete or dependant test failed
--
MID:$a2 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 1 Data
Test incomplete or dependant test failed
--
MID:$a2 TID:$80
- Misfire Cylinder 1 Data
Test incomplete or dependant test failed
--
MID:$a2 TID:$81
- Misfire Cylinder 1 Data
Test incomplete or dependant test failed
--
MID:$a3 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 2 Data
Test incomplete or dependant test failed
--
MID:$a3 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 2 Data
Test incomplete or dependant test failed
--
MID:$a3 TID:$80
- Misfire Cylinder 2 Data
Test incomplete or dependant test failed
--
MID:$a3 TID:$81
- Misfire Cylinder 2 Data
Test incomplete or dependant test failed
--
MID:$a4 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 3 Data
Test incomplete or dependant test failed
--
MID:$a4 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 3 Data
Test incomplete or dependant test failed
--
MID:$a4 TID:$80
- Misfire Cylinder 3 Data
Test incomplete or dependant test failed
--
MID:$a4 TID:$81
- Misfire Cylinder 3 Data
Test incomplete or dependant test failed
--
MID:$a5 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 4 Data
Test incomplete or dependant test failed
--
MID:$a5 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 4 Data
Test incomplete or dependant test failed
--
MID:$a5 TID:$80
- Misfire Cylinder 4 Data
Test incomplete or dependant test failed
--
MID:$a5 TID:$81
- Misfire Cylinder 4 Data
Test incomplete or dependant test failed
--
MID:$a6 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 5 Data
Test incomplete or dependant test failed
--
MID:$a6 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 5 Data
Test incomplete or dependant test failed
--
MID:$a6 TID:$80
- Misfire Cylinder 5 Data
Test incomplete or dependant test failed
--
MID:$a6 TID:$81
- Misfire Cylinder 5 Data
Test incomplete or dependant test failed
--
MID:$a7 TID:$0b
EWMA Misfire counts (average) for last 10 drive cycles - Misfire Cylinder 6 Data
Test incomplete or dependant test failed
--
MID:$a7 TID:$0c
Misfire counts for last/current driving cycles(calculated) - Misfire Cylinder 6 Data
Test incomplete or dependant test failed
--
MID:$a7 TID:$80
- Misfire Cylinder 6 Data
Test incomplete or dependant test failed
--
MID:$a7 TID:$81
- Misfire Cylinder 6 Data
Test incomplete or dependant test failed
--

End of report.