I recently changed my spark plugs on my S-Type and I got a code that came up P0305 comes up as cylinder 5 misfire. Had no codes with old plugs, installed new Bosch plugs and code comes up. Could it be bad plug ? I know I dropped one plug and didn't think much of it if that matters ? I was also driving and engine light came turned off a little later, only turns on when you floor it. Anyone have any ideas before I go buy other brand plugs ? Thanks

 

If the MIL is flashing when you accelerate under full throttle, catalyst damage is occurring.

Swap coil unit of cylinder 5 with that of another cylinder to see if the DTC changes to that cylinder.

 

Usually a bad coil. Check for water/oil when swapping.

 

Anyone happen to have a diagram of the numbered cylinders for my vehicle? (Vehicle in signature)...I couldn't find one on the net.

Thanks

 

Here is the cylinder numbering layout for the AJ-V8.

 

Vehicle not showing in signature

Exact MY of car really matters for numbering.

 

If coil unit is bad would engine warning light be on constantly ? The light hasn't came back on recently even under HEAVY acceleration. Car feel fairly normal

 

Without vehicle info we are wasting typing effort!!!
V6 or V8????????????????????????

4.0 or 4.2???????????????????????

good luck

bob gauff

 

I thought I had my vehicle info in signature but guess not.

2005 S-Type Sport 4.2L V8