Hey there everyone I am new to posting to this forum, but I often use it to diagnose issues with my vehicle so I'm hoping you guys can help me out. I own a 2003 Land Rover Discovery with around 130,000 miles on the odometer, my car is my daily driver, and is 30 miles from home, left sitting because I have had a problem suddenly arise with my rover that has left me feeling unable to drive it. My car has been running great for the last year, no major issues, but today when I went to start up my car after work I noticed it was running very very rough, shaking violently and the check engine light was flashing, I pulled out my code scanner and the codes given were P1319, P0303, and P0300. From my understanding P1319 is related to a misfire detected with low fuel level. I will say my car was inside the empty tank line when the issue occurred, and over the last 6-8 months Ive picked up a habit of constantly driving the vehicle on a quarter tank to almost empty. I know that can't be good for the fuel pump or filter. My theory is that the last few months of driving on low has caused a build up or block in the fuel system. Im planning on filling the tank up and adding fuel system and injector cleaner and letting it run hoping it cleans up the issue. Im not sure why my car went from running amazing, smoothly, no codes to being practically undrivable in the span of a few hours. I also want to add that I've changed the spark plugs, wires, and ignition coils about 15K miles ago. Please help if you can I need my car up and running asap.

 

You answered your own question regarding your CEL and running rough, but I would advise to run a fuel cleaner through the system and possibly turn to the fuel pump if that does not solve your problem.

 

Misfire is unrelated to fuel level. Swap #3 plug with #5, then wires, then coils (l to r).

 

Code 0303 is a good clue for misfire cylinder 3. So, could be plug, or wire, or coil, as Extinct alludes to above. Swapping components will help pinpoint what failed. Unfortunately, any of these components can fail in less than a second.

 

If swapping wires/spark plugs doesn't do the trick, being that you've already changed coils recently, do a quick compression test. Once these drop below about 90 psi cold compression they will set off a miss fire. Doesn't take much carbon build up on the seats from a PO running cheap fuel to cause an issue.

I tossed on a set of heads that I had decked, thought to myself they have less than 85k on them, there's no way they need a valve job. I had to pull heads right back off and do a valve job.


The eBay/Amazon coils seem to be pretty good. Only a couple brands of plug wires would be considered acceptable/reliable.
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