misfire issues

So i just bought a 98 Discovery and it has some issues. When i take it out for a drive it run fines for a couple miles or so, then it starts misfireing badly. The power comes in waves. The CEL was on so i took it to get the codes read. The there were 7 codes, i somehow only managed to write down six. The codes were P0300, P0305, P0304, P1316, P1314, P1313. I think the code i missed was cyl 7 misfire. It also has a high idle issue. The plugs and wires are all new. what do you think is causing all this misfireing?


thanks for your help.

update since i cant figure out how to edit.

General Pcodes were
P0300 - which is just a general multiple misfire code
P0305 - cyl 5 misfire
P0304 - cyl 4 misfire
P0308 - cyl 8 misfire

Manufacture Pcodes
P1313
P1314
P1316
P1316 (came up twice this time)

How many miles are on the Disco?

You say plugs and wires are new... What plugs did you install?

When did the issue start happening? Was there any work down just prior to the issue?

What type fuel are you running?

Last fuel filter change?

Last air filter change?

119k miles

Previous owner installed most likely generic Advance Auto brand wires and NGK plugs

When did the issue start happening? Just got the vehicle, started happening on my first drive that was longer than a couple miles.

Was there any work down just prior to the issue?
I replaced the steering box yesterday(PITA), fuel pump, wires, plugs, shocks replaced about 2 weeks ago.

What type fuel are you running? Previous owner said all he ran was 91 octane (highest around here), so on my first fill up i put 91 octane in it

Last fuel filter change?
No idea

Last air filter change?
Yesterday, put in a paper fram air filter

Thanks

i put some new champion plugs in it that i gapped today. took it to town was still misfiring. checked all the stores around and none of them carry wires for the rover. As it is now, it has Autolite Professional Series 7mm wires in it that were replaced about 2 weeks ago. I looked closely at the wires last night in the pitch black and saw no arching. So while i was driving around town the speedo quit and stopped working. i pulled onto the interstate because it "seemed" to misfire more at high speeds yesterday. i drove 20 miles on the interstate and it hasnt misfired since the speedo stopped working in town. still has a high idle

Part of your issues sounds like the vss to me. I had alot of the same problems with my own. Its easy to test, try to unplug the sensor located on your rear wheel (do a google search or search on here). Your speedo not working is a sure sign. Good luck, and let us know what you find! ps, my problems were the vss and the computer. Once I replaced both of those, it ran beautifully all last winter!

Issues will be the VSS if the issue went away after the speedometer stopped working.

it wasn't the VSS, issue still undiagnosed

Quote:

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Originally Posted by inhUMaine

it wasn't the VSS, issue still undiagnosed

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I would have a l;ook at your alt, check connection and the voltage out put