Misfire

I'll let you see wat you think!! " I pick the car up Sunday from Wales 320 mile trip home spot on no problems park it up Monday go to the car do at least 50-70 miles in it fine no problems then go to it Tuesday starts up and then misfires and won't clear" and it's been like that ever since just starts up but misfires constantly I've done
Dizzy
Coil
Spark plugs
And MAF sensor but is still throwing up error code 12 on the fault code check so it's saying MAF sensor but done compression test spot on cross all 4 cylinders? WAT DO YOU THINK??? Help

Did you buy it from newport?

No mate why? I bought it from Pembrokeshire

Bloke in newport was selling an R and he not really trustworthy .

What fuel did you run it on?

What leads and plugs ????
Have you tried re earthing the maf ?

Where is the earth mate in the connection?

Leads are just standard and plugs recommended by Bob..

Its the middle one think its normally a white wire splice and solder another piece of wire to it and ground off onto the chassis...

Ok cheers mate and I ran it on super unleaded..

Is it earthed already then or not? And where bouts is it earthed?

Yeah its earthed already wich is the white wire but if its not earthing out properly by doing this it will be ....

Right then earthed out the MAF sensor no joy still misfiring? Dunno wat else it could be?

Ok so tell us abit more about the spec of the car .... boost controller ? Turbo ...etc is it standard what set up etc???

Did you fit a new rotor arm when you put a dizzy cap on?

Is it actually mis firing or running on 3 cylinders Matt?

Bob I really don't know wats up with it mate? I've done compression test and it's all good cross all 4 cylinders? Wen are you able to have a look at it mate need it sorting ASAP really start new job in 2 weeks? Always the way ain't it? Me personally I think it's misfiring..!!

And GTI_R_IOW The arm look brand new in it but no I didn't change it?

Did you change bits before the miss fire?

Silly question but no pipes have come lose?

As the earlier post, is it misfiring or running on three cylinders, does it run rough/misfire when at idle, if so you can disconnect each lead from each plug one at a time, if the engine note changes (and struggles to continue running) it means it is firing on that cylinder OK, when the engine note does not change that is your offending misfiring cylinder, then have a closer look at the plug and lead.
After running have you removed the new plugs and inspected for oiling or a wet plug (fuel)? it may point you in the right direction.
Good luck.

Just make sure the plug lead aint breaking down or it will shock you and its not a nice feeling

No there not mate HT lead are fine mate I ain't got a clue thank you for every1 trying to help me I'm dropping my car off at bob's later?

Just a thought have you tested the coil ....

Yea I have mate

Thermal wrote:As the earlier post, is it misfiring or running on three cylinders, does it run rough/misfire when at idle, if so you can disconnect each lead from each plug one at a time, if the engine note changes (and struggles to continue running) it means it is firing on that cylinder OK, when the engine note does not change that is your offending misfiring cylinder, then have a closer  look at the plug and lead.
After running have you removed the new plugs and inspected for oiling or a wet plug (fuel)? it may point you in the right direction.
Good luck.

Have you tried the above? And is it fine on idle or running rough the whole time? Have you checked boost pipes/dump valve to make sure they haven't popped off