misfire under light throttle?

[crispy1980]

Hi guys, basically as per title my car has started to misfire under gentle throttle. This seems to be worsening as time goes on. Last night the car really jerked as I approached a roundabout with the car under no throttle. Seemed to be at the point I pressed the throttle down. In thinking either plugs, leads or coilpack ? Does seem to be worse in wet weather, but was at its,worst last night in the dry?

 

[zinc2000]

If it runs ok from cold then gets worse as it heats up then it sounds like the coil pack is on its way out.

I think it might be worth looking at the fuel filter just to see if it maybe needs replacing as well, just in case its a fueling problem although if problem occurs off the throttle it seems unlikely..

Hope that helps

 

[crispy1980]

I had wondered about the fuel filter. Maybe under heavy throttle its forcing fuel through?

 

[zinc2000]

Fuel only gets through the filter under pressure from the pump, full or part throttle will have no effect on that pressure so the only problem will be dirt in the filter, worth replacing if you cannot cure the problem any other way.

 

[748]

This sounds like coil pack to me. I had very similar symptoms recently, went straight for coil pack replacement, fixed it.
Trouble is they're not cheap and if you replace it and it doesn't fix it then you have to move on to something else.
At least you rule it out though.
If you don't know the history of the plugs it's worth replacing them also.
Paul.

 

[Ziggy]

Other alternatives to check are TPS and MAF, can you borrow known good ones to try from another puma ? both are easy to fit and see if that sorts it. Maybe sort out a puma meet

 

[crispy1980]

Strangely been fine since. Think I'll have to wait until symptoms worsen