Hi, and thanks for reading.

First post here, so hope I've got this in the right place, apologies if not.

Car model 1.25 Zetec engine Mk5 Fiesta 2001/2002 standard model, Petrol

Car has been running smoothly, and well for the last few weeks, but this morning there was a sudden change, first noticed by a distinct lack of power when changing gears and accelerating. Quickly after this the engine management light came on - first time it's done this since I've had the car (about 2 and a half years)

Car idling roughly, and there's a noticeable judder when pressing accelerator, struggling for power.

The symptoms above got worse in a very short space of time over the morning. A kind neighbour who knows more about car/mechanics than I do has helped narrow things down a bit, before it went to local mechanic I regularly use later this afternoon.

We did the following:
Tested spark plugs - all fine (only replaced last October in service, good quality set as well) - all dry and no water fluid leaking into where the plugs are.

However, testing each plug in turn, the only noticeable and 'extreme' drops in power when the engine is turned over come from plugs 1, 3 and 4. When we tried it from the original rough idle with plug 2 disconnected there was no significant change, until later when the problems gradually got worse.

Checked all connections/leads where we could from a quick under bonnet look, and all seemed fine.

On a very quick up and down the street drive just to see any more symptoms of problem, noticed the following - Engine management light went from staying on 'solid' to flashing when the revs went above 2000. Over the morning this changed to a constant flashing as the engine was switched on, so this issue has got worse. Looking under the bonnet and there is a slight burning smell, and the CAT was very hot.

Limped at no more than 40-45 mph to local mechanic about 15 mins away, got there (eventually) and car was noticeable losing power, fast. uphill was a real struggle, and you could smell a 'burning' smell while driving, and a 'chugging' noise, symptom of a misfire coming from exhaust.

Local mechanic has had car this afternoon, and done the following:

Changed coil pack for new - no change to symptoms.
Swapped plugs around, no issue with the plugs themselves.

He also initially did a compression test around the no. 2 plug 'chamber (correct term?) with an older tester, noticed no compression, so thought it might be valve - = BIG money, cylinder head off etc.

Went across tonight to pick up loan car from him, and he had managed to get hold of a modern compression tester piece of kit from a local mot centre/garage, he connected it up to No. 2 'chamber' and turned engine over - needle on kit went right up to 120-130, showing this is 'working'. - so hopefully not valve.

With this in mind, he has suggested that he's going to change leads to plugs tomorrow in case no. 2 lead has failed. If not , he has thought it might be injector. - after that he's into a 'process of elimination' territory.

The CAT was getting very hot - also noticeable smell of petrol when turning engine over, particularly when with him tonight, so I assume petrol is laying in cat and not being burned.

The chap did put a code reader on at the start, and only codes that came up referred to the misfiring that was happening, thankfully no error codes for the CAT, so hopefully I haven't melted that away this morning given the petrol and 'burning smell'

I guess any advice may help if anyone has had similar issues. I'm not mechanically minded when it comes to cars (my training is making buildings work, not engines!) so any advice, thoughts or pointers would be helpful. Best/worst case scenarios also accepted.


Again, many thanks for reading, and thanks for any replies/help you can offer. Happy to answer questions if I can, but please excuse any 'non-technical' phrasing from me.