Chk Engine Lt - Code P0306 and P1316

[whiskeynipple]

98 Disco - stock 75k v8

Check Engine light came on - got the following codes and definintions:
P0306:
Definition:
Cylinder misfire detected-Cylinder number 6
Explanation:
The powertrain control module monitors the crankshaft speed and has detected a misfire condition.
Possible Causes:
1-Ignition system fault-spark plug(s), ignition wires, coil
2-Vacumm Leak
3-Injector fault
4-High or Low Fuel pressure

P1316
Definition:
Spark plug voltage detection circuit fault- Left bank (2)
Possible Causes:
1-Poor Connection at spark plug Voltage Detection Module (VDM)
2-Open or short circuit between VDM and ECM

I believe the last tune up was around 50k (now 75k) - Ive owned it since 61k - have not replaced the plugs or wires since ownership


NOTE: I have noticed recently (when very damp or cold) a throbing acceloration when at cruising speed and accelerating on incline

the vehicle still starts and revs and accelerates as it always has.

I hope the first code caused the second - My first thoughts are change the spark plugs then wires

any suggestions?


thanks

 

[joey]

I would agree... start with plugs and wires, but you may also have a carbon build up issue on the exhaust valves.

 

[whiskeynipple]

Joey - would carbon buildup on a valve throw a code? (I always use shell or BP 93 octane)or is that a response to the throbing acceleration

If plugs and wires dont do it - should I go for seafoam next?

thanks

 

[joey]

I would do the seafoam next if the plugs and wires do not work.

Remember it isn't the quality of fuel that burns the carbon off, but driving it hard enough to get things hot. If you do a lot of around town driving, then carbon will build up. Hard highway miles are better than local driving. Same principle as why cars that are driving local tend to rust out the exhaust, but if you drive it long enough to burn off the condensation, you have less issues.

 

[whiskeynipple]

yeah I do mostly local driving

but get this - the check engine light is off......
I didnt clear it - I did drive 45 hwy miles last night (light was on) and was kicking it down a few times.
could this be a bigger problem- should codes really clear themselves?
either way Im doin plugs

 

[joey]

Yes codes will clear themselves after so many cycles (not sure how this really works, but it does), if it does not repeat any codes.