Car has run fine for months but last week it suddenly started misfiring, then a few mins later it would clear and be fine again for a while as if it never happened. The other day it started again and became really bad to the point I couldn't keep it going. I stuck a new coil and new points on it and it was faultless again for about 50 miles then suddenly started the misfiring. I stripped and cleaned the carb, checked float chamber etc, no obvious faults there but when I put it back together it's just as bad as it was before. All the leads are fine (ie I don't get a shock when I run my hand over them and they are fairly new
).The misfire doesn't seem to alter depending on amount of revs or speed or amount of load, gear I'm in etc, it almost feels like there is a fuel blockage which cleared temporarily but is not now clearing. That said my suspicion is that it is electrical because when it's spluttering and farting I'll try and rev it, sometimes it goes, sometimes it dies but when it starts dying off if it cathces again it sometimes explodes from the rear with a real bang and black smoke. That suggests to me that fuel is passing through the system, not being ignited until there is a spark at which point the unburnt fuel in the exhaust ignites? I'm not saying thats correct, just my impression.
Also, when it's running (badly) I've whipped off the leads one by one and held them to the block and there seems to be a strong spark while it's running relatively smoothly but as it starts to struggle the spark disappears. I'm pretty confident the timing is there or thereabouts and after new (correctly set) points and a new coil I'm guessing the condenser is shot. If thats right wouldn't it just die and not temporarly 'come back'? I'll be getting a new condenser anyway as soon as I can find one nearby but any other suggestions welcome. I'm not very technically minded so short words and explanations welcome
Thanks in advance,
Rob
