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Ford Focus 2 1.6 Petrol - Fault Code P0304 - Pete Mansell

This car, at 45000 miles, suddenly started running very badly, and the engine management warning light started flashing, but did not remain on. The car felt like it had a fuel problem, as if running out of petrol, and wouldn't go above 50mph.

The main Ford main dealer hooked it up to their test equipment today, and diagnosed fault P04304 - misfire on cylinder 4. They replaced one plug lead and all 4 plugs, and reset the ECU.

Needless to say, tonight the car was little better. It was hesitant at all speeds, and the management light flashed at over 50mph. It wasn't quite as bad as before, but clearly not right.

It will be going back tomorrow, but does anyone know what they are likely to do next. Hopefully they won't just start changing parts - the coil pack next?

I would add that the car has not been re-fueled for over a week, so bad/wrong fuel shouldn't be a problem.

Ford Focus 2 1.6 Petrol - Fault Code P0304 - GBP1705

Iv'e had a similar prob with my 52 Avensis. Diagnostic machines says random misfire.

It regulary fires on only 3 cylinders and is i go above 3000 revs it loses all power.

I'ts been in 3 different Toyota dealerships and 4 independents, none can find the problem

Ford Focus 2 1.6 Petrol - Fault Code P0304 - unthrottled

Those zetec engines are notorious for coil pack failure due to the oversized spark plug gap. it's worth sorting out misfires because extended running with a misfire does destroy the cat-and you'll need a new cat-and a new exhaust manifold and flexi section because the garage usually makes a bodge of welding the new cat in.

Ford Focus 2 1.6 Petrol - Fault Code P0304 - bazza

The early Mk 2 1.6 had a design fault where rain water drips into the spark plug wells and onto the coil pack area. Very common fault, causes symptoms like this. Ask garage if they noticed any water/rust when changing plugs? I suspect coil packs as per Unthrottled and a colleague had very similar with same car a month or two back.

Ford Focus 2 1.6 Petrol - Fault Code P0304 - Pete Mansell

Thanks for the comments. I was aware of the water leak problem, and checked that first, but all was dry. I suspect the coil pack, but thought it may be a waste of money changing things without checking the fault code. It will be interesting to see if there is now a different fault code.

I wish they had spent as much time on the fault, as they did on other 'spurious' things. They couldn't even have done a road test or they would have been immediately aware it wasn't fixed. The car came back washed and vacced, and a list of things they said needed doing - brake fluid change (done by them last year), rear indicator bulbs going white (they weren't), re-gas air-con, clean/adjust back brakes, replace wipers. All this would have come to an extra £181 + vat. The car wasn't even in for a service - just for the fault. I am disappointed as I have used Polar Ford for 10 years and they have always been great.

Ford Focus 2 1.6 Petrol - Fault Code P0304 - Pete Mansell

Update. They have just phoned to say it still says fault P0304. They tried swapping the coilpack with no success. They tried swapping the injectors between cylinders 3 & 4, but it stays with 4.

They will get their specialist electrical guy to look at it tomorrow, but have offered me a courtesy car for the weekend. At least they aren't just fitting and charging for more and more parts!

Ford Focus 2 1.6 Petrol - Fault Code P0304 - Pete Mansell

A strange end to this saga. The car has just been returned with the fault fixed, but they weren't sure what it was! They suspected a wiring fault, and the cableforms around the top of the engine appear to have been pulled apart and taped up.

Anyway, I have just done a 40 mile drive and it didn't miss a beat. What puzzled me the most was that there was no extra charge beyond the initial diagnosis and repair charge, despite an extra 5 days spent on it.

Just as I was beginning to doubt Polar Ford in Stockport, I feel a bit better about them now - as long as the fault doesn't return!


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