Newbie here...please help.

Just bought a dealer maintained 03 disco with 70K.

This morning, no extreme weather, got a p0304 + p0455 fault. SES light also came on. Called the dealership and the 60K service had been performed that included new plugs but not wires. Had the emission test done Saturday so I checked the gas cap and it was not secured. I tightened it and the SES light went of and seems to be driving fine. No cheap gas, no significant leaks or anything of the sort.

Q: Could the misfire and gas cap incident be related since the RAVE manual lists the P0304 fault as 'Injector 4 excess emissions/catalyst damaging level of misfire' and the gas cap is part of emissions control?

Your input is greatly appreciated.

P.S. If the wire(s) are bad, can a fairly technically inclined person do the job?

Thanks,
///M

 

A loose/bad/missing gas cap will not throw a mis fire code, it will throw a EVAP leak code.

Yes plug wires can be done buy a Shadetree Mechanic.

 

So it's the wires I assume since the plugs were done only 10K ago?

Thanks for the help.

///M

 

Yes, in theory if you can unplug and plug in wires to a connector then you can change your own wires. It takes a little patience to do it with out taking off the upper IM.

 

Thanks.

I found the Deepbluewater post with pics so I'll give it a go.