Misfire?

Hi. 2002 1.4 petrol. The car has been starting well and has been serviced once in the 18 mths since we bought it but recently a couple of things have started to happen: 1) Intermittent extremely low revs on starting. Sometimes it then stalls and sometimes it just sits there chugging at a couple of hundred rpm (according to the dial and by the sound of the motor) and after a few seconds revs increase to normal. Giving it some right foot on the gas doesn't seem to make any difference while this is happening! 2) Some intermittent hesitation on acceleration. I use premium unleaded because I did initially find that the car misfired occasionally using the basic stuff. I have also put in a bottle of injector cleaner but the hasn't made any difference. I'm in two minds wondering if this is a fuel problem or an ignition problem. Anyone have similar experience? Thanks.
 
Also have a 2002 1.4i (AUA). Just passed MOT flying colours on emissions after I got the injectors cleaned and replaced the coil with a brand new Bosch one (having already replaced plugs and leads with Bosch ones) - it's running better now than at any time since we had it. Throttle body and EGR were new last year. Of those I believe firmly now the coil and the cleaned injectors contributed most to the massive improvement in running / lack of misfires although the other bits will have contributed significantly to the health of the engine. Worth having a look at your coil, particularly around the back of the casing as they do crack in places that aren't readily seen and that makes the likelihood of weakened sparks somewhat higher, especially in the damp (and especially further if the leads aren't in prime condition).

Does yours get worse when it warms up or at certain rpm or is it only on startup? Are there any other symptoms?

VCDS is a good shout although if the problem is just misfiring and cylinder shutdowns that won't necessarily tell you what the actual problem is. On ours to begin with there were EGR and throttle body errors that were fixed once the dead EGR and really dirty original TB were swapped out and re-adapted ; subsequently it was error-code free despite the uneven idle and mis-firey-ness around 16-1700rpm part throttle that suggested other stuff was going on. Finally a few weeks ago the misfire got worse and worse to the point of cylinder shut-downs (and was being picked up by the misfire counter on VCDS without a specific error being obvious) hence the suggestions here that injectors needed cleaning / servicing and I found the structural issues with the original coil and replaced this. Hasn't misfired once since and has been running markedly better (and more fuel-efficiently in my hands).

Re-reading your original post made me wonder if it is something to do with fuelling at the time when in older cars you might use the choke? Fuel temperature sensor?

best of luck, Robin
 
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I had similar problems before. I find it best to use NKG spark plugs as they were fitted from the factory and definitely improved my engine.
 
Thanks. Coil also occurred to me. I'll take a closer look. I hadn't aligned this hitherto to a particular weather situation although it's been the last couple of months, so that could be part of it. As far as engine temp is concerned, it's mainly on warm-start rather than cold-start, which seems weird to me.

Also have a 2002 1.4i (AUA). Just passed MOT flying colours on emissions after I got the injectors cleaned and replaced the coil with a brand new Bosch one (having already replaced plugs and leads with Bosch ones) - it's running better now than at any time since we had it. Throttle body and EGR were new last year. Of those I believe firmly now the coil and the cleaned injectors contributed most to the massive improvement in running / lack of misfires although the other bits will have contributed significantly to the health of the engine. Worth having a look at your coil, particularly around the back of the casing as they do crack in places that aren't readily seen and that makes the likelihood of weakened sparks somewhat higher, especially in the damp (and especially further if the leads aren't in prime condition).

Does yours get worse when it warms up or at certain rpm or is it only on startup? Are there any other symptoms?

VCDS is a good shout although if the problem is just misfiring and cylinder shutdowns that won't necessarily tell you what the actual problem is. On ours to begin with there were EGR and throttle body errors that were fixed once the dead EGR and really dirty original TB were swapped out and re-adapted ; subsequently it was error-code free despite the uneven idle and mis-firey-ness around 16-1700rpm part throttle that suggested other stuff was going on. Finally a few weeks ago the misfire got worse and worse to the point of cylinder shut-downs (and was being picked up by the misfire counter on VCDS without a specific error being obvious) hence the suggestions here that injectors needed cleaning / servicing and I found the structural issues with the original coil and replaced this. Hasn't misfired once since and has been running markedly better (and more fuel-efficiently in my hands).

Re-reading your original post made me wonder if it is something to do with fuelling at the time when in older cars you might use the choke? Fuel temperature sensor?

best of luck, Robin
 
Thanks. Coil also occurred to me. I'll take a closer look. I hadn't aligned this hitherto to a particular weather situation although it's been the last couple of months, so that could be part of it. As far as engine temp is concerned, it's mainly on warm-start rather than cold-start, which seems weird to me.
If you can take the bonnet off in the evening when it’s dark & damp you can normally see the high voltage jumping about , don’t be tempted to touch it though!
Hth
Keith
 
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