I've still not been able to diagnose this issue. The other day, I went out on a slight cold night, car seemed fine as I drove out onto the road but I put my foot down to accelerate and nothing seemed to happen for a split second then it just suddenly accelerated. Never done that before! Driving up the road it misfired like a bast**rd in fourth breifly before evening out again. FUel consumption is still higher than normal.
While I think replacing the coil pack has worked to cure the intermittent misfire it seems there's another problem that was there too which is unrelated to the coil pack breaking down.
I've searched a lot (not just with mondeos but cars in general) for things that can cause issues with increased fuel consumption and as far as I can tell, it could be any number of one of these (and perhaps any number of others but these seem to all be the ones that come up when searching):
- Coil pack is always the first one people seem to suggest but I know that isn't the problem obviously as mines now brand new.
- ht leads breaking down - mine seem fine, I have tested them and found no obvious issue with them.
- sparks failing - I took out the three on the front of the engine (only seeing as the ones at the back are a bitch to get at), they don't seem to be fouled beyond general wear and tear for 5 year old plugs (turns out they were ngk ptr5d-13 as suggested I replace with earlier in the thread so they should be good for 50/60k miles as far as I've read, and these have only done 30k).
- o2 sensors up the duff. I have no idea where any of the 02 sensors are on this engine. No doubt somewhere extremely difficult to get at judging by everything else.
- fuel pressure low - which could be caused by a blocked fuel filter, dodgy fuel pump, buggered fuel pressure regulator.
- injectors buggered
- vacuum leaks - can't find any
Any other suggestions for me to check? I'm assuming the fact no ones replied for weeks other than myself is because you've all run out of suggestions and ideas anyway. Me too. :|