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2007 RRS HSE
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65 Posts
Discussion Starter #1
My 1997 P38 4.6L was throwing the "usual" collection of codes which I pulled up with my Nanocom: P0303, P0300, P1313. I first replaced the spark plugs, ignition wires (8mm) and the coil for cylinders 2 & 3, and kept getting the same codes after resetting the MIL. I finally diagnosed it to a faulty fuel injector (cyl. 3 per P0303) and replaced that, which took care of P0303.

I am still pulling P0300 & P1316 this time, and don't know what to do next! Some additional info which might be of relevance: I am also pulling a P1775, which is transmission related, and to be addressed once I resolve the Ignition/Fuel issues, and in all cases (pre and post injector replacement), the truck runs and shifts just fine.

What should I look at next? I'm utterly puzzled.
 

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1995-2002 Range Rover Classic
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1,413 Posts
clear all codes, p0300 multiple misfires p1316 generic for emissions relevant misfires, 1775 transmission fault possible due to lack of engine torque again related to misfires.
check your wires for cracks, proper connections, proper contacts and or damaged coils. basically recheck all your work and clear all codes before retesting.
 

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2007 RRS HSE
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65 Posts
Discussion Starter #3
I think I spoke to effin fast! I'm back to square one today, as I pulled the codes again with my Nanocom and not only did P0303 come back, I also got P0302 (misfire cylinder 2). Apparently there was nothing wrong with the fuel injector I replaced, otherwise I shouldn't have gotten that same code again.

check your wires for cracks, proper connections, proper contacts and or damaged coils. basically recheck all your work and clear all codes before retesting.
95classiclwb: What wires are you referring to? Can you please be more specific? Thanks.
 

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Spark plug wires. In other words, inspect and clean your ignition system to ensure proper spark.
 

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2007 RRS HSE
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65 Posts
Discussion Starter #5
Spark plug wires are new (STI 8mm), so are spark plugs. Ignition coil packs look like they had been replaced by the previous owner (don't know when), but they are too new and shiny to be the originals that came with the truck.
 

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1995-2002 Range Rover P38A
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Spark plug wires are new (STI 8mm), so are spark plugs. Ignition coil packs look like they had been replaced by the previous owner (don't know when), but they are too new and shiny to be the originals that came with the truck.
Just 'cos something looks new and shiny, doesn't mean that they were/ are quality and properly functioning components though. A plethora of cheap Chinese knock-offs on the market.
 

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2007 RRS HSE
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65 Posts
Discussion Starter #7
Just 'cos something looks new and shiny, doesn't mean that they were/ are quality and properly functioning components though. A plethora of cheap Chinese knock-offs on the market.
True, but I forgot to mention that they are the factory original part, not an aftermarket copy.


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1995-2002 Range Rover Classic
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I think I spoke to effin fast! I'm back to square one today, as I pulled the codes again with my Nanocom and not only did P0303 come back, I also got P0302 (misfire cylinder 2). Apparently there was nothing wrong with the fuel injector I replaced, otherwise I shouldn't have gotten that same code again.



95classiclwb: What wires are you referring to? Can you please be more specific? Thanks.
ignition wires of course. as others have said, just because they are oe and new does not mean they are functioning well.
you're missing something, double check your work. are the plugs gapped right? miles and maintenance on your engine? have you inspected your cam for proper lift (hint worn out cam).
are your injectors plugged in correctly and secure? other than the misfire how does the engine run? any knocks, taps other noises?
again double check your past work. you may have missed something.
 

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2007 RRS HSE
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65 Posts
Discussion Starter #9
There was no change as to how the engine was running prior to and after replacing the spark plugs and wires. The engine is running the same, which is to say normal, no knocks, taps or other noises. I changed the wires and plugs as this seems to be the 1st logical thing to do when you have a mis-fire. The truck seems a little sluggish from a stand still, compared the the '96 HSE I owned right before that one, then again, I am running 32.5"x11" tires compared to the factory 29"x10", which I think contributes to the lag.

The plugs I installed are the Bosch Platinum +4 (I know I'm going to get a ton of criticism for not installing NGK), and they are pre-gapped, and finally, all injectors are plugged in correctly, and secure. I double checked.

I have not checked the cam, or the other "usual suspects" yet, such as O2 sensors and crank sensor. I can log a CSV file of the ignition/fuel system (short & long term fuel trims) with my Nanocom, but have no understanding on how to interpret the readings.
 
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