My 2000 Discovery is giving me a p1300 code. It runs fine when driving normal, but seems to run on less then 8 cylinders when trying to accelerate from a light. It also idles a little rough sometimes. One time it backfired out of the intake when accelerating hard. Any idea what could be causing this? I do plan to change all 4 O2 sensors this weekend because of the milage on them. I don't know if that is the problem though.


2000 Discovery II, 181,500 miles

These ignition/fuel parts were change
Bosch +4 plugs 60,000 miles ago
Magnacore 8mm 60,000
new maf 100,000
front O2 sensors 80,000, rear O2 sensors never changed

Thank you,
Willie

 

Pull your plugs and check the condition. The new O2's will help.

 

What octane gas are you running, when was it last tuned with new 8 mm plug wires?

 

I was experiencing misfires on cylinders 3 and 6 and got those codes as well as P1300. I changed the plugs, switched to Magnecor 8mm wires and gave it a can of 44K as suggested here...and the problems and codes were resolved. I've driven about about 300 miles and everything seems ok. I figure that is a pretty good shakedown cruise.

Great advice. I followed the sticky advice on how to change the wires...it took me almost 5 hours....but it worked out well.

 

I cleared the code yesterday, today I have a P0174 code system too lean in left bank. I have 60,000 miles on the magnacores and bosch +4. How long are they supposed to last? I only run 92 octane. I will check the plugs. Where did you buy the 44k? I can't seem to find it around here in Washington. I just replaced the head gaskets. Do the lower intake bolts ever need to be retorqed? I was just wondering about a possible vacuum leak. I checked the upper intake and exhaust manifold bolts, they were all tight.

Willie

 

I just checked all of the sparkplugs. They are all dry and apear to firing. All of the passenger side plugs were black soot covered and all of the drivers side were white.

Willie

 

Those plugs and wires will be good for close to 100,000 miles.
Napa has the 44K, great product.
That 1300 code is a random emission misfire usually tied in with another cylinder misfire. Be patience, it will raise it's ugly head with time.

 

Do stored codes have anything to do with new problems? I am still getting a new code P1300 and several stored codes. I have new O2 sensors on the way and I put seafoam in the gas tank.
Willie

Here is the print out from my test.




MIL DTC P1300Catalyst damaging misfire multiple cylindersDrive cycle C:Signal out of range - above maximum

Conditions For Setting This Code:
Possible Causes:
Monitor Information:

Stored Codes P1590ABS rough road signal circuit malfunction
Conditions For Setting This Code:
Possible Causes:
Monitor Information:

P0154O2 sensor circuit no activity detected (bank 2, sensor 1)
Conditions For Setting This Code:
Possible Causes:
Monitor Information:

P0135O2 Heater Circuit (Bank 1, Sensor 1)
Conditions For Setting This Code:
Possible Causes:
Monitor Information:

P0155O2 Heater Circuit (Bank 2, Sensor 1)
Conditions For Setting This Code:
Possible Causes:
Monitor Information:

P0308Cylinder 8 Misfire Detected
Conditions For Setting This Code:
Possible Causes:
Monitor Information:

P0306Cylinder 6 Misfire Detected
Conditions For Setting This Code:
Possible Causes:
Monitor Information:

P0302Excess emissions level of misfire detected on cylinder No. 2
Conditions For Setting This Code:
Possible Causes:
Monitor Information:

P0300Random Misfire Detected
Conditions For Setting This Code:
Possible Causes:
Monitor Information:

P0304Excess emissions level of misfire detected on cylinder No. 4
Year: 2000
Manufacturer: Land Rover
Make: Land Rover
Model: Discovery II
Engine Type: V8, 4.0L; EFI
Tranmission: Automatic
Trim Level: SD
Mileage: 182000



=== Stored Error Code(s) ===
Error Code: P1300
Possible Causes:

Error Code: P1590
Possible Causes:

Error Code: P0154
Possible Causes:

Error Code: P0135
Possible Causes:

Error Code: P0155
Possible Causes:

Error Code: P0308
Possible Causes:

Error Code: P0306
Possible Causes:

Error Code: P0302
Possible Causes:

Error Code: P0300
Possible Causes:

Error Code: P0304
Possible Causes:



Freeze Frame Information:
1. DTC for which Freeze Frame was Stored - P1300.
2. Fuel System 1 Status - Open Loop - Due To Detected System Fault.
3. Fuel System 2 Status - Open Loop - Due To Detected System Fault.
4. Calculated LOAD Value - 21.57 %.
5. Engine Coolant Temp - 195.80 °F.
6. Short Term Fuel Trim - Bank 1 - 0.00 %.
7. Long Term Fuel Trim - Bank 1 - 0.78 %.
8. Short Term Fuel Trim - Bank 2 - 0.00 %.
9. Long Term Fuel Trim - Bank 2 - -14.84 %.
10. Engine RPM - 1,455.50 Rpm.
11. Vehicle Speed Sensor - 38.52 Mph.


Monitor Information:

1. MIL - ON.
2. Misfire Monitor - Complete.
3. Fuel System Monitor - Complete.
4. CCM Monitor - Complete.
5. Catalyst Monitor - Not Complete.
6. Heated Catalyst Monitor - Not Supported.
7. EVAP Monitor - Not Complete.
8. Secondary Air System Monitor - Not Supported.
9. O2 Sensor Monitor - Not Complete.
10. O2 Sensor Heater Monitor - Complete.
11. EGR Monitor - Not Supported.
12. NMHC Monitor - Not Supported.
13. Nox Adsorber Monitor - Not Supported.
14. Boost Pressure System Monitor - Not Supported.
15. Exhaust Gas Sensor Monitor - Not Supported.
16. PM Filter Monitor - Not Supported.

 

I think I was reading the tester wrong. It looks like all 10 codes in my previous post are new. I erased it in the vehical then tested it again and the reader said no codes 0/00. They will come back again when I drive it next time. It looks like it is a O2 sensor problem. Could a coil also be going bad?

Thank you,
Willie