Code P1151

Good afternoon,

What misfire codes? You said nothing of them. Can you give me all the codes that were set?

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

The 1151 has many possibilities. I posted them below.

https://www.2carpros.com/articles/how-an-oxygen-sensor-works

https://www.2carpros.com/articles/how-to-test-an-oxygen-sensor-02-sensor

Did you check the fuel pressure? Low fuel pressure will cause the misfire codes.

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Roy

DTC
P1151
Symptom Descriptor
Lack Of Ho2S-21 Switch, Sensor Indicates Lean
Probable Causes
Air Induction System Leak after the Mass Air Flow (MAF) Sensor
Air Leaks After the Mass Airflow (MAF)
Camshaft Timing
Camshaft Timing Incorrect
Cylinder Compression
Cylinder Compression Incorrect
Diaphragm or EGR Vacuum Regulator (EVR) Leaking
Engine Oil Dipstick
Engine Oil Dipstick Incorrectly Seated
Excessive Fuel Pressure
Exhaust Gas Recirculation (EGR) Valve
Exhaust Gas Recirculation (EGR) Valve Malfunction
Exhaust Gas Recirculation Valve Solenoid (EVR)
Exhaust Leak
Exhaust Leak Before or Near the Heated Oxygen Sensor (HO2S)
Fuel Injectors
Fuel Injectors Leaking and or Contaminated
Fuel Pressure Excessive
Fuel Pressure Low or Insufficient Fuel
Fuel Pressure Regulator
Fuel Pressure Regulator Leaking
Gasket Leaking
Harness or Heated Oxygen Sensor (HO2S) Short to Ignition Switched Power (VPWR)
Heated Oxygen (HO2S) Sensor
Heated Oxygen Sensor (HO2S)
Heated Oxygen Sensor (HO2S) Circuit Open or Shorted
Low Fuel Pressure or Running Out of Fuel
Oil Overfull
Overfilled Oil
Poor Mating Terminals and Wiring or Corrosion
Positive Crankcase Ventilation (PCV) System
Powertrain Control Module (PCM)
Powertrain Control Module (PCM) Damaged
Vacuum Leak
Vacuum Leaks
Vapor Recovery System
Water in Harness Connector

Fuel pressure was 285 at 3,000 rpm's. The original misfire code was P302. After replacing the fuel injector it resolved. 3000 miles later I got P304, P305 and P306 and Bank 2 Sensor 2. I replaced those 3 injectors and the O2 sensor, as well as plugs, plug wires and coil pack. Still have the rough idle like I did with misfire codes present. I now have no other code but the P1151, which isn't supposed to create driveability issues, but they're there.

I should clarify, 285 KPa according to the scan tool.

The 1151 is not causing the issues.

The rough idle could be mechanical. I would start by checking the compression.

https://www.2carpros.com/articles/how-to-test-engine-compression

The spec is 30-50 key on, engine off.

Roy

I'll check that tomorrow and let you know what I find. Thanks very much for some direction.

You are welcome.

Always glad to help.

Roy

Okay, so compression check complete:

Cylinder 1 200
Cylinder 2 190
Cylinder 3 190
Cylinder 4 160/240 (w/oil)
Cylinder 5 90/150 (w oil)
Cylinder 6 190

Okay, you have an issue with number 5. 90 is way too low and you have unburned fuel exiting the cylinder and that will set the code.

From the readings, you have a ring issue with the change with oil.

https://www.2carpros.com/articles/replace-engine-piston-rings

Looks like that is the issue.

Roy

Yeah, I don't think the car is worth the time/money to repair. Pistons rings etc., are outside my ability. I assume if we keep driving the car it will eventually result in catastrophic failure.

Correct. It will eventually fail on you altogether.

Roy

Thanks so much for your help!

One more thing, is there any value in using a thicker oil viscosity?

Not really. It would help with worn main and rod bearings but not with compression.

Roy