Miss Firing - Help Please

[smartestsmarty]

Hello all,

I believe my engine is miss firing, so I assume I would need to change either the coil pack, spark plugs or leads.

Is there a way to find out which one would need replacing?

I would like to do it myself.

any advice would be appreciated.

[BobbyBCFC]

Unfortunetly not. This needs to go on a Computer. Its not expensive.

My partner has a MK5 Fiesta also. We took it to the local garage who said number two (not the technical number) was miss firing. Therefore I changed the coil pack, spark plugs and leads.

However on inspection. I found that the spark plug wells were full of water which had probably filled up over a year or so. Might be worth checking that. Get the water out and you should be fine, bare in mind the spark plugs may have rusted due to this.

Your water jets let through water as they are not sealed down properly (Ford manufacturing fault). This is why water gets to this area. This is a known/common problem. Seal them down with Silcone should do the trick.

If this does not work, could be coil pack etc.

See how this goes.

[smartestsmarty]

Unfortunetly not. This needs to go on a Computer. Its not expensive.

My partner has a MK5 Fiesta also. We took it to the local garage who said number two (not the technical number) was miss firing. Therefore I changed the coil pack, spark plugs and leads.

However on inspection. I found that the spark plug wells were full of water which had probably filled up over a year or so. Might be worth checking that. Get the water out and you should be fine, bare in mind the spark plugs may have rusted due to this.

Your water jets let through water as they are not sealed down properly (Ford manufacturing fault). This is why water gets to this area. This is a known/common problem. Seal them down with Silcone should do the trick.

If this does not work, could be coil pack etc.

See how this goes.

Ahh thanks a lot for your reply, is there a guide on how to remove the spark plugs to check?

[BobbyBCFC]

Get yourself a Haynes Manual. Always useful. Book knows more than the mechanics.

Might be a Video out there somewhere.

It should be as easy as.

1. Remove the Air filter, should slide out

2. Remove Engine cover. Screws likely. Sorry not with the car or manual.

3. Pull out the rubber plugs.

Remember it is important to know the exact torque wrench setting when putting new spark plugs in. Found in Haynes Manual

[smartestsmarty]

Thanks,

Also, how do you change the leads and coil pack?

I will try get hold of a Haynes Manual.

[BobbyBCFC]

Sorry, it is an DIY job, easier than brake pads etc but far too many steps to put down here.

Again if you can't find a video or a detailed guide on here. Haynes Manual gives you a great step by step guide. Should get commisson from Haynes me thinks.

[smartestsmarty]

Sorry, it is an DIY job, easier than brake pads etc but far too many steps to put down here.

Again if you can't find a video or a detailed guide on here. Haynes Manual gives you a great step by step guide. Should get commisson from Haynes me thinks.

Thanks again,

If its easier than brake pads, then i'll have no problem :)

[BobbyBCFC]

If you check the water situation. Let us know B)

[smartestsmarty]

I got a full service today, so sparks were changed, the issue itself is a lot better, however it hasn't completely gone.

It still judders when accelerating, if the speed is kept constant it is smooth.

What does this point to?

any suggestions?

[stef123]

Unfortunetly not. This needs to go on a Computer. Its not expensive.

its highly unlikely the computer will show up anything with regards to coil, leads or plugs. if you had the EML light on the dash it would probably indicate whatever cylinder is showing a misfire but it wont know whats causing the fault

if the spark plugs are ok then there is a chance it can be the leads or the coil - unfortunately, there isnt really any way of checking them.