First, a bit of background. I've just been on annual leave, we went for a drive up north for a week and a bit and visited some places. Anyway, we drove all fine and dandy until we were around Marton. We pulled into Marton to find a public loo, and when i pulled out onto the main highway and put my foot down the engine had no pull. None. It was increasing in revs at a rate of like 100rpm per second. I tried driving like that for a bit and pulled over to check if i'd blown something. Engine smelt fine, no smoke, it all seemed tickety boo. So i took off again, same issue. Anyway, we had to keep on going, so i nursed my car (now capable of doing 0-100 in literally 40 seconds) to Taihape (including one section where i had to drop from 5th to 2nd just to get up a pretty easy hill... i got overtaken by an old lady in a Fiat)...
Once we got to Taihape, i called by a mechanic who suggested i take it by an auto sparky. The sparky checked the spark plugs and noted immediately that they were pretty rooted. While he was there, he checked the leads with a multimeter and said they pretty much checked out, and that they had a problem in SW20's with the leads splitting, but they seemed ok. He also did a compression test, which came out fine. So replacing the sparkplugs (with normal ones not platinums, coz thats all he had), we fired the car back up, and drove off, all seemingly fine.
Anyway, a couple of scares along the way doing what i'll describe later, but we got to Hamilton without major incident. It had been pelting down with rain the whole way so i thought i better check the airfilter wasnt clogged since i hadnt changed it since we had it. Didnt know how to open the airfilter container
so took it to a mechanic who whacked the air filter in, and in the process noticed i was still running the original factory fuel filter. Removed that, watched thick black sludge the consistancy of Caramello chocolate exit the old one, replaced it. Drove all the way the rest of the trip without major issue.
The only remaining problem, and its one i can sometimes duplicate and sometimes not, is as follows : When you try and accelerate off a gear higher than usual, the engine has the same problem with no power, until it hits about 2.5krpm, then all of a sudden all the power is back on tap and away you go. For instance, if i drive up to a small roundabout behind someone travelling slowly, drop down into second and coast around the roundabout in second. Exiting the roundabout i'm doing say 5kph and am on about 1200rpm, if i put my foot down, it just feels like the engine is a 750cc gutless wonder for about 1-2 seconds until the revs hit about 2-2.15krpm and then all of a sudden its all go again. And it only happens in circumstances like that when you try and pull away under load in a gear one higher than perhaps you should be. Its not very common, its only done it 4-5 times since the trip north, and never before that.
Any ideas what could be wrong? My father in law suggests the spark plug leads are faulty, so i've priced up some and its a reasonably cheap option. But any other thoughts?
Off topic slightly : the only other thing weird with it is that sometimes when you walk past the car when its off you can hear a momentary 'electrical sparking' (it sounds like) noise coming from the back left corner of the engine (between the distributor and radiator cap)... its only momentary. Me and a mate noticed it in Wellington, but it only lasts for a half second and occurs randomly at perhaps 5-10 minute intervals. Any idea? We couldnt see any sparks, but it sounds like a sparking of some sort.
Cheers!
) And charkol box is part of the emmission control system is it not?? SO revheads idea makes more sence 
