HI All,
My mk2 punto with 150.000 miles has misfire.
I changed coil pack,leads,plugs and lamba sensor.
When the car is at low rpm its mis fires and when you leave your foot on the acelerator and rev it really hard it seems to go away.
But when you press the accelerator it mis fires really badly,until it hits the high rpm.
Any ideas what is causing this?????????????????????
tony

I have recently 'cured' a tickover/low speed misfire by changing the idle control valve. This was on a Grand Punto so I dont know if its the same as yours.

I work on both..family and friends.

Hi tony did any of the plugs you take out have oil on them or have any of the new ones got signs of any ? Is car losing any oil / blue smoke ? If so it’s maybe valves / gasket or rings possibly

the car has been using more oil than normal and the plugs are black and sutty.
The engine has 151000 miles done.
Dont see any blue smoke from exhaust.

TONY55S said:

the car has been using more oil than normal and the plugs are black and sutty.
The engine has 151000 miles done.
Dont see any blue smoke from exhaust.

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Yeah but can you make it clear if your plugs are wet or dry?

Seems like they are dry so the worn engine is not creating really big problems to cause the misfire

The plugs are dry.
So what should i be checking to sort out the air fuel problem?
tony

Hi tony the plugs being dry doesn’t mean your out of the woods but if their sooty it’s unlikely Coolent is making it to them but I take it the new plugs are clean I’d be studying them maybe after not driving it for a night , I notice you didn’t change the oil / this prob is starting to look electrical but an oil change with a 10w40 semi synth and good filter might help if the valves are worn , I suspect slight oil or (hopefully not Coolent is hitting a plug ) possibly, the fact that it’s worse when you start it or idle hints at a buildup at offending plug them it burns off on acceleration