pickup not running

Hi have a 1990 toyota pickup carb. 4cyl. I let it sit for 4 weeks came back and it wouldnt start unless it was jumped, let it run for about 20 min took it to les schwab to fix a tire and wouldnt start they replaced the battery while there. Then later while driving it died at a stop sign and would start up (it did once but died right away). I checked the plugs and all 4 were all completely black 2 were fairly new (within 2 months). I replaced/cleaned (1) all of them, got a jump and it ran exactly the same (barely idling like only running on 3 cylinders). Not sure if needing a jump to start is related or not to not running right (plugs all bad) but....a little history on the pickup, replaced engine a month or so ago and timing has never been right, mechanic said he needed to go in the engine and time it not the timing you can change by moving the distributer (using the little machine it says its timed right but its not)(certain rpm's it will cut out a little and has not much power, this I think is why it fowls plugs (before at least) it has done it 2 times before when I accelerate too fast. anything would help thanks

Depending on how long it took to die after replacing the battery, the needing a jump all the time I would say your alternator (I don't know how long of a drive it is to les schwab) As far as fouling all four plugs, I'm not sure. The timing, the only thing you should need to adjust in the engine is the chain or gear. I don't think the timing being off could foul your plugs like that. Which rpm's is it cutting out at? (lower,higher)

Pull the alt canadian tire will bench test for free if you don't have one take it to any shop it's usually 10 bucks for a bench test if it tests good check you grounds then fusable links. Good luck Tom Canada