I just took it for a run with one of my mates to see if we could asses what the problem could be. I discovered that the problem doesn't occur if I take above 5.5 and push through up around 6.5-7k mark. I could only get it to happen when I take it from 5.5 and change gear between that and 6-6.5 -- now this could be purely coincedental, I'm unsure, but it took me 4 runs to get it to start doing this and it was there that it did it. I don't take my car in to MiVEC all that often so let's say for arguments sake that this problem only occurs if I change gears during this range, causing it to drop out of MiVEC after only just entering it.
What happens is sort of hard to explain. The exhaust noise becomes deeper, I get what sound like mini back-firing noises sometimes, in the lower RPM range 1 - 3k it runs like crap and struggles to get power. If I take it back up in to MiVEC RPM range, anywhere from 4k+, it gets power back, runs fine, and the noise from the exhaust goes back to normal sound.
This problem almost always goes away by taking it back in to MiVEC range and changing gears at the right spot, but the right spot varies once this has started -- just as it appears to vary to make it happen. Also sometimes just putting it in park and revving the crap out of it, making it jump in and out of MiVEC range, which i really dont like doing.
So what we've deduced from our total lack of understanding in how MiVEC actually works is: whatever triggers the process at 5.5k is variably malfunctioning, and it's not taking the engine out of MiVEC mode. Which from the sounds of it is causing the engine to over-fuel or something when in the lower RPM range.
Wondering if anyone has had any experience with this issue; something similar, or could help me understand what could be causing the issue and/or how to get my mechanic to fix it.
I could be totally wrong as to what the problem is, but this is was our conclusion based on the evidence we gathered. Any help will be appreciated
