[Mk2] [Turbo] Odd running problem

[Harold]

Ever since I gave the car a good snow foaming and pressure wash a couple of weeks back I've had an odd problem.

For the first 10-15 mins of any journey while driving at a constant speed I will get an intermittent judder/hesitation and also a reluctance to rev until I reach the boost threshold and once that kicks in it drives as normal. Also in this first short period of driving, if I'm sat at idle it will occasionally drop to 4-500 revs and not sound normal at all, requiring me to give it a bit of throttle to keep it up. But once I've been driving for a while the car performs just as it should.

I've checked over the standard ignition components, dizzy cap is fine and was brand new 6 months ago, rotor cap looks in good condition, plugs are clean and tips are a good colour, coil is a brand new aftermarket part also installed 6 months ago.

This problem only occurred after the pressure washing and I'm not sure what to look at next.

Any pointers chaps?

Cheers guys.

[markstevieandmads]

check the ht leads?

If its been after washing then id assume cap or rotor but if you have checked these then there is a few other checks.

Take the coil off and give the bracket and where it mounts to the car a good rub down with some sandpaper as this earths through the bracket.

Sounds like its definitely ignition related though.

[Marf]

Pull the coil off, turn it upside down, are there any cracks?

[Scantily]

Hello,

This is the OP here, for some reason I can't login to my original account. Hopefully one of the mods can fix it.

There has been a further development, the car was started this morning then turned off shortly after. On attempting to restart it the car was completely dead and still is. Nothing happens when you turn the key, headlights don't work, central locking not activating, nothing.

The car didn't struggle to start the first time, I drove around 70 miles yesterday and only had the ignition issue mentioned previously which stopped after 10 minutes. I checked for error codes a couple of days ago and all clear and the battery is only a few months old. Haven't had a chance to check the coil, but an ignition component wouldn't cause this problem would it?

I don't think this is a battery issue, possibly an immobiliser problem? What else would completely shut the car down?

Couldn't have happened at a worse time, the girlfriend was supposed to be using my car today as hers needs to go into the garage.

[Scantily]

Disconnected the battery, left it for a few minutes before reconnecting and as if by magic power is restored and engine starts up perfectly.

Anyone have a clue as to why this might have happened?