What ive done so far:

 

Changed the spark plugs.

 

Changed the coil connectors - all the plastic bits were broken.

 

Took the PTU off and cleaned all the pins - started the car and it sounded fine, shortly after the missfiring started.

 

Just done an ECU diagnostic - got the code 55 so no faults

 

Surely it cant be the cas as the ECU showed no faults?

Im thinking its the coils, what does everyone else think?

Quite likely to still be the PTU.

 

I would swap around coilpacks to rule them out first.

 

(ECU is'nt 100% in showing faults with PTU/CAS/MAF)

Also worth trying removing each coil pack connector 1 by 1 and replacing 1 by 1 whilst engine is running and see if the engine note drops as each connector is removed.

Bad PTU can be non starting and bad signals sent to coil packs.

If your not a series 2 PTU, tbh it's always worth upgrading.

smithy

If you manage to locate the offending coil pack swap it with the one next door. If the misfire then moves to the other cylinder you know its the coil pack, if it stays on the same cylinder you know its the connector/wiring.

 

I have found that the 15 year old wiring has been subjected to that much heat over the years that it becomes brittle and breaks easy.

 

Ed

Typical, its one of the ones unber the balance bar. I think its the one on the right (if you look at the engine) i'll swap it and see. Its all fun fun fun!

Ok i swapped the 2 under the balance bar because i wasnt sure about them both. After they were swapped round i started the engine and checked them.

 

Before i couldnt get the plug off the one on the right under the balance bar, but when i swapped the coil i moved a few wires around and was now able to unplug it and see if the noise changed....

 

With the engine on, i checked all the plugs and listened for a noise change, they all made a different tone when all unplugged which means it cant be a coil, right?

Least thats something mate, however bear in mind the PTU is like 6 minature transistors sending signals to the coil packs, imo it's worth swapping for a known good one and especially a series 2 one. There have been reports from some people that they have noticed a sharper/quicker responce after fitting the series 2 PTU's.

cheers

smithy

It would make life much easier if you could find someone locally with a ConZult or Datascan.

Forgot to say, theres more popping and noise coming from the drivers side exhaust.

 

Would that mean that its one of the cylinders on the drivers side that is broken?

Just read through this, am I missing something? Have you checked the injectors and the plugs to them, that could be the cause of a mis fire.

Dont mean to sound fick but where are the injectors and plugs?

i'd like to ask that as well! It might be a fuel shortage in one cylinder which would be an injector or the cas as it controls them. If one exhaust is poping more than the other then it would indicate that bank has the problem.

try another ptu first mate, i think the plenuim has to be stripped to get to the injectors etc (correct me if im wrong please).

I went out in it today, it was a bit rough to start with and could only get 40mph out of her without it sounding really bad.

 

I stopped to fill her up with petrol, after that it sounded fine. Didnt have a single pop from the exhausts, no noise or anything. Would that mean it is the injectors?