Anybody Got Any Ideas Of What To Do Next

[bongoboy]

I appologise in advance if this post is a bit long winded.

i have a hyundai getz,
About a year ago it was running rough (No engine management light on.) took it to the garage who changed the HT leads after putting it on the computer which solved they problem (this was about 1 year ago)

In December had new mid section exhaust fitted to pass MOT. the last few months the engine management light has been on (amber) but running ok, just lately it has been it has been running a little bit rough which has slowly got a bit worse but only up to about 5 minutes or so from cold but amber light stays on.

last week i changed the oil and oil filter
air filter
spark plugs
and it is still the same

i have taken it to a garage and they put it on the computer and the result was it was misfiring on no 4 cylinder and they said it needed a new coil. Changed both ignition coils (£126) yesterday and today the engine management light has come back on and running slightly rough (not as bad as it had been) just for a short time, so obvisously that was not the problem, what a waste of time and money.

Does anyone know what to try next?

many thanks

[tonyav]

Take your car back to the garage bongoboy, they have miss diagnosed the problem.

[Iggle Piggle]

Have someone check the lambda sensor (in the exhaust pipe). What kind of rough running is it ? does it idle ok? does it rev smoothly ? does it lose power when it's rough ? does the roughness clear up once the engine is warm ?
cheers

[bongoboy]

Hi
iggle. Thanks for responding.
Ticks over perfectly even when cold.
It's only rough when cold (left over night) and when driving, which is for the first 5 mins of the day. After that it's fine even if left for several hours before going out again.
Seems to be mainly when accelerating when cold (slightly jerky).
Not sure if it loses power or not, it may well do. I will take more notice when i drive home from work in the morning.
It's always been an almost silent engine when ticking over although there now seems to be a slight tapping unless it's because i'm looking out for things now. Could it be a valve clearance problem? Although they may well be hydraulic and self adlusting for all i know .
Does a garage have to have a specific computer to give you an error code such as an Hyundai dealer. As all i got from Mr clutch after putting in on their PC for analysis was "Number 4 cylinder misfire) So it's probably your coil.

[tonyav]

Yes your car will need to be plugged into a computer for the ECU to tell it what fault(s) have been stored in it's memory. You don't have to go to an Hyundai dealership ( although they would definitely have the software, but probably be expensive ) but I would not trust the likes of Mr Clutch, Kwikfit etc.

[Iggle Piggle]

Hmmm, odd one but I'd be aiming at fuel line - filter, injectors, pump.
When was the car last serviced? have you got the paperwork and was the fuel filter changed? It could be a clogging injector, you could try a gentle 'blast' down an open road, holding 3500 to 4000 rpm for a few minutes.
There are fuel additives that claim to clean injectors, i'm no fan of these but it won't hurt for a few quid.
The computers that read a cars ECU are fairly generic, you don't need a dealer to read the errors. I can do Fiat and VW/Audi cars on my laptop !