Technical car misfiring but don't know why

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Technical car misfiring but don't know why

Ali786

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My fiat Grande punto 2009 1.2 petrol is misfiring but no engine light on dash. so I change coil pack and leads and it still misfiring. any can help pls
 
And you also changed the spark plugs and the ht leads are routed correctly so that they don't have contact with each other? Also they're properly installed, not loose or anything like that. (y)

How about the pcv hoses, one from the airbox and the other which goes into intake manifold? As suggested above, check coolant level and check for signs of leakage. If the coolant had been low, the headgasket fault is possible with high running temperature.

The last thing is a faulty ECU which might become damaged for running a long time with poor spark plugs. Did it have poor plugs?
 
And you also changed the spark plugs and the ht leads are routed correctly so that they don't have contact with each other? Also they're properly installed, not loose or anything like that. (y)

How about the pcv hoses, one from the airbox and the other which goes into intake manifold? As suggested above, check coolant level and check for signs of leakage. If the coolant had been low, the headgasket fault is possible with high running temperature.

The last thing is a faulty ECU which might become damaged for running a long time with poor spark plugs. Did it have poor plugs?
coolant is all good I haven't checked the sparks plug but I have a feeling it a faulty ecu. if it is a faulty ecu all I would need to do is buy a new one and will it need programing or anything ?
 
coolant is all good I haven't checked the sparks plug but I have a feeling it a faulty ecu. if it is a faulty ecu all I would need to do is buy a new one and will it need programing or anything ?
Take out the plugs..
20220916_151608.jpg


Line them up in cylinder order

Then show a Pic


They should all be a similar colour :)
 
First change the spark plugs to see if it helps. (y)
 
First change the spark plugs to see if it helps. (y)
i will check the spark plugs when im next free thanks. by any chance do u know why sometimes i start my car it makes a loud screeching noise and then i need to start the car again.
 
Very difficult to guess, but it could be a failing starter motor, poor battery,poor main earth.
 
o_O Oh sorry for not being too specific. Start from the cheapest, buy new earth lead (chassis-battery-gearbox) and then recharge the battery. It's a very bad idea to change original parts when they're not completely broken. Original parts can last the lifetime of the car, when spare parts are failing every other year. I did that myself but then understood that ultimately it's very expensive way to fix things that don't really need to be fixed.

How about those spark plugs? Did you change them, does it run better now? You should get the cylinder pressures tested to know the condition of the engine. All of this would be in vain if the engine was worn out. Does it consume a lot of oil? Old cars do that if the car had been on long-life oil program.
 
o_O Oh sorry for not being too specific. Start from the cheapest, buy new earth lead (chassis-battery-gearbox) and then recharge the battery. It's a very bad idea to change original parts when they're not completely broken. Original parts can last the lifetime of the car, when spare parts are failing every other year. I did that myself but then understood that ultimately it's very expensive way to fix things that don't really need to be fixed.

How about those spark plugs? Did you change them, does it run better now? You should get the cylinder pressures tested to know the condition of the engine. All of this would be in vain if the engine was worn out. Does it consume a lot of oil? Old cars do that if the car had been on long-life oil program
Sorry for late reply. I changed the spark plugs just now I’m going to go for a little drive and see if it helped. Spark plug 1 is on the left
 

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Yes, these should have been replaced years ago. An obd reading would have revealed that the ignition was missing.
I always start with OBD for these kinds of errors.
If I buy a car. I always change the spark plugs, fluids, lubricants, timing belt, alternator belt, filters. I don't care what anyone says when it was replaced. Paper can handle anything. I've seen a 3-year-old car regularly serviced in a specialist garage, which was brought to me to see why the engine was noisy. The oil and oil filter were changed so long ago that the engine ate the paper insert of the oil filter, leaving only a small stub.
 
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