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So here goes, my 34 is making a strange subtle popping noise around 1-2k revs under no boost and every now and then it's detonating when under boost around 4-5k revs. What the H is this gremlin?

Before this problem started I had changed the spark plugs with Ngk platinums, exactly what was already fitted and running fine for years. During that process I had a couple of the coil pack connectors snap on me and wouldn't click back on on two of them. I thought maybe it could be the connectors so I bought brand new ones and fixed them. Nope, same thing still happening, grrr.

Just after I changed the plugs myself I took the car to a reputable workshop to have the water pump and timing belt service done as I am nearing 100,000 kms. This is the only thing I am thinking could have gone wrong. I drove around for a week after the plug change and had no issues, after my timing belt was done it seemed to start happening.

Is it possible the workshop messed up the timing or something??

Could one of my coil packs be on the way out?

Something else entirely?

On a cold start it hits full boost like normal and seems okish, maybe a little detonation. After maybe 10 minutes its like it goes into safe mode, boost won't go past 4 psi and the popping starts and more detonation starts under full throttle. It sounds like misfiring to me, but wouldn't it do this all the time, even when cold if it was a misfire issue? Which leads me to think the timing has been retarded or is out?

I will call the workshop which did the belt change and question them but not sure how I will go accusing them of wrong doing. I am thinking of buying spitfire coil packs to eliminate that from the list but would rather avoid spending 400 bux if its not necessary.

Anyone got any ideas, suggestions or experience with problems like this? I would really appreciate the input, cheers.

Update : Ok, so I ended up taking my car back to the workshop who did the timing belt change. I waited for a couple

of hours while they "checked it over". They rang me and said they couldnt fault my car and that I could come pick it up

unless I wanted them to dig further into possible ignition issues such as coil packs and spark plugs at my cost. I said

nar dont worry bout that I'll just come pick it up. I picked up my 34 and drove home giving it a good bootful once it had warmed

up. Not once could I get it to detonate or run like it was 3 hours before or like it had been for the last couple of weeks.

The worst thing that happens now in the last few drives I have taken it on is that it sometimes decides to only hit 4-5 psi

and other times 9-10psi but very rarely compared to before when it was constantly only boosting to 5. I am at a bit of a loss

now... Did the workshop stuff something up and then fix it when I took it back and not want to admit it? They re-checked

the timing and said it was at 15 degress base timing which it is supposed to be apparently. Maybe they just happen

to fix the issue when they checked it and didnt realise it? I'm not sure at all. All I know is as long as it runs smooth like it

is and should be then it doesn't matter for now. Btw my car still runs stock dual stage boost, my only mods are a cat back

exhaust and a k&n panel filter. So like I said, I'm at a loss. Maybe it was the workshop, could be one of the coil packs just starting

to break down, who knows. My next thing if it gives me any more trouble will be to buy all new splitfire coil packs and even

though I have almost no mods go and get a Nistune and hope that either finds the problem or irons it out.

id say they did set the timing wrong and realised this when you brought it in. But as if they are going to say that. They would have just set it right and given it back with said story.

You should have checked where the CAS was at before and after.

Man i give my left nut to be able to hide a secret camera under the hood when dropping it to the workshop... (which i do as infrequently as possible now)

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