View Full Version : Diagnostic Help

09-19-2007, 12:38 PM
I need help with a diagnostics on my vehicle.

On a recenn trip to Canada (280miles each way) the "check engine light" came on on my 02Disco. After checking with the local auto store for codes (autozone) I got the Oxygen sensor errors.

I then replaced the front O2 sensors. Also replaced the mass airflow meter assembly.

Engine light came back on.

New codes P0300, P0302, P0306, P0307 ( multiple cyl misfire, cyl 2 misfire, cyl 6 misfire, cyl 7 misfire)

I then replaced spark plugs and plug wires. Also performed oil change with engine flush (in case valves were stiking).

Latest readings are P0300 and P0307, but only when I rev my vehicle to 1500 RPM or above. I can have it on idle for ever with no "check engine light" coming on.

What should I replace now? Coild Pack? Rear O2 sensors?

Or should I get it inspected by the dealer? ($$$$$$$$$$$$$$)

09-19-2007, 02:43 PM
did you clear the codes after you completed the work? if not you could still have old codes, if you have replaced the plugs and wires and still have (multiple random misfires) its always the coil pak, when ever you perform work to rectify a code always clear or erase the previous codes that way you are starting fresh and not confused by old codes.....

09-28-2007, 06:55 PM
OK, after replacing coil pack, new set of spark plugs (second set in last few weeks ). I keep getting the same codes. And yes I erase them after every repair I do.

Here are the codes I got today.


Where do I go from here?

Please help!

09-28-2007, 07:11 PM
did you replace the coil pak with a (NEW) land rover unit ? or a used one? if it was used this is such a common problem with these you probobally got a bad unit, if it was new did your plug wires some how get mixed up when you replaced them? if all this checks out i would look at the crank sensor and start testing, but now these procedures are not for the lay person.....

10-07-2007, 03:04 PM
I apologize for the late reply.

Yes, I bought a brand new BOSCH coil pack for my vehicle.

(I also replaced the plug wires, and plugs. I have checked the wire and plug installation several times to make sure I hae everything in the right order.)

All original equipment.

Same codes. (P0300 , P0307 and P0306).

What about the injectors? or Rear O2 sensors?

I will check the crank sensor and post my feedback.

Thanks for the help.

10-07-2007, 07:38 PM
the O2 sensors will only send out a o2 sensor code, and the injectors will not send a code, stop wasting your money by trying new parts you need an experienced tech to check crank sensor output, ECM,and wiring.....

Robison Service
10-20-2007, 03:26 PM
If all the ignition parts are new, and installed correctly, and working as they should . . . then you probably have valve trouble within the engine. You can remove the plenum and valve covers and check for tight valves by removing the springs and feeling how tight or free they are . . .