Hello All

My new to me 5.0 s/c has developed a P0302 error. Cylinder 2 misfire. It appears after 5-10 mins as a pending error, and will turn on the EML after another 10 mins or so.

I fitted new spark plugs - error still P0302.
I swapped cyl 2 coil pack with cyl 4. error still P0302.

At this point, I looked at fuel trims, and they were -13 and -18, so I suspected an injector.

So I fitted a new injector into cyl 2, and guess what, the P0302 is still there along with the same double digit fuel trims.

So, to confirm, cyl 2 is passenger side, at the front of the engine.

The car drove 100 miles home with no issues or EML. Since then it has been started for a few seconds or minutes only each time as it is shunted around as I fitted new brakes, oil change etc. I have allowed it to fully warm up on a number of occasions.

What else do I check? Compression test? But why was it fine beforehand and now this? Anyone any ideas? 2010 5.0 SC Autobiography Overfinch in Bentley Silk White pearlescent, 22" Overfinch wheels with 285/35x22 tyres

I initially read the codes using an Autel handheld code reader. It can also display live data, like fuel trims etc. Anyway, I used the JLR SDD and it displayed misfire errors on all 8 cylinders along with a P0316. The SDD listed the TSB I asked about here:
https://www.fullfatrr.com/forum/topic69557.html
The SDD also suggest a reconfiguration of the PCM. I managed to perform this.
However, the misfire remains.

I then went back to basics and did a compression test on the Cyls 2,4 6 & 8 bank.
Oh dear. At least I have found the fault:

Cyl 2 40psi
Cyl 4 110psi
Cyl 6 145 psi
Cyl 8 135 psi

Me thinks I have a warped head. I have realised I have a coolant leak from the back of the engine but I have had no indications or warnings of overheating.

I rebuild the Ford 3 cyl ecoboost engines as a past time. Obviously like this V8, the early ecoboost cars give no advanced warning of overheating (whereas the later ones do).

What a "enter profanity here". 2010 5.0 SC Autobiography Overfinch in Bentley Silk White pearlescent, 22" Overfinch wheels with 285/35x22 tyres

Just think of it as a 2 and a quarter ecoboost engines and you'll be fine  L405 SV Autobiography LWB SDV8, finished in Aston Martin China Grey by ETO division.

I appreciate the RR and Fiesta are at opposite ends of the spectrum but I have seen family similarities between the 2 when working on the RR engine.  2010 5.0 SC Autobiography Overfinch in Bentley Silk White pearlescent, 22" Overfinch wheels with 285/35x22 tyres