Mk4 Gti agu misfire

[Hawkins92]

As above i have a mk4 gti with agu engine code, 141k miles..
From other posts seems completely stock bar few missing items, it recently began misfiring but im fortunate in my godather having a garage so down the yard i went, fuel filter sparks etc all changed to no avail.
Tried using his diagnostic but wouldn't connect to port so went old school, pulled each plug and bingo cylinder 3 is misfiring, swapped coils/ sparks round & still on 3.. Cleaned up ignition amp n no change, i do have a new amp being delivered today but was wondering if this doesn't change anything what other possibilities there are for misfire?
I know i do have a split hose on the notorious pcv & im putting the final touches to diy catch can but could this cause the misfire? Car sounds like a scooby!

[lemski]

Is it losing water? Just had an s3 that misfired on cyclinder 2. Headgasket was gone

[Hawkins92]

No its not, all levels are spot on, i do need to fit the new thermostat that came so ill do a full flush at that point but apart from that everything else is all as should be, its had us puzzled, last step really will be stripping all eletrical connections for the coils but a bit daunted by this

[lemski]

Being an agu it is probally the ign amp. They drop one coilpack first.

Swapped an injector, see if the fault moves?

[Hawkins92]

Im hoping it is the ignition amp to be honest be such a nice easy fix haha, fingerscrossed!

Ive not yet no, I'll try that if amp doesnt sort the issue, thanks for the suggestion & help!

[Wazzzer]

Most diagnostic readers don't work with the AGU but VCDS will

[Hawkins92]

Cheers for the info wazzzer, amp arrived done a dry install till can get some thermal compound and walla! Running like a dream 😉

I am looking for anyone who has vagcom vcds in sefton/southport area to do a fault read just so i know whats going on with it.

[Hawkins92]

Wow! When I originally got the car I didn't realise the n75 had been bypassed.. Bit of research showed me this haha, just installed a new one & holy boost i thought it was quick before, you can actually feel the car now pulling 🙃

[lemski]

Why would anyone bypass the n75. Unless they were trying to bypass something else and got it mixed up

[Wazzzer]

There aren't many fault codes that will turn up on the AGU but N75 faults deinitely will