Fuel Pump

[Tintin]

Is this the same problem you were having under "4 litre XJS coughing" that you though was fixed?

If it was the F pump I would have expected the problem to be worst under heavy fuelling demand - and that doesn't seem to be the case.

I had a similar issue with my AJ16; the things I looked at/cleaned/replaced to try and fix it included:- fuel pressure relief valve; O2 sensors; cam cover EGR hoses and heated bypass valve; throttle body (several times); coolant temperature sensor; CPS; IACV; TPS and voltage; ECU plug/connections in N/S footwell; MAF sensor and voltage; general vacuum leaks on inlet side. I also took it to a Jag specialist to get a readout of the engine codes with the proper jaguar diagnostic kit. Looks like you have already replaced the coil packs plugs and CPS. I also gave the fuel tank a shot of Cataclean.

Good luck!

Robbie

[MichaelSB]

Hi Robbie
No, this is a recent issue which feels fuel related, your list is a long one, did it resolve your issue?
Michael

[Tintin]

My intermittent misfire has not completely gone but it is now sufficiently rare that I can live with it.

Fuelling is sensor/ECU controlled, so any of the points I listed (and more) could be causing a rich/lean mixture.

R