pur1138

Howdy. Poked around here and search looking for some answers, but....

Bought this truck about 2 months ago. Nice shape. Very little rust. 117,000 miles. Standard trans. Carb. Z24 motor.
Sometimes it will run well for a week. Sometimes it gives me fits about every day.
Starts nice and quick and runs real smooth most of the time, but occasionally it will start to lose power. Keeps running smooth, but you have to keep downshifting while looking for a place to pull off the road. After I've pulled off sometimes it will keep idling smoothly but even flooring it doesn't get the revs up very high. Sometimes once you've pulled off it will die or run really rough as it dies.
Letting it sit for 3 or 4 minutes allows it to start right up again. Sometimes after this point it will run great and other times after awhile it will start losing power again.
HAHA! A trip to work is a real adventure! Sometimes I have to do it in chapters! :P

Anyway, replaced the electric fuel pump and filter and a bunch of vacuum hoses ( many were in bad shape and seemed to help it not do this as frequently) Checked timing. Been running gas treatment through it regularly.
If I'm not totally mistaken, there may be some kind of outside temperature relationship. When it's warmer than low thirties it seems to do that whereas if it's in the 20's or lower it doesn't.
There is one item the previous owner did that if I undo it, it won't run at all.
On the driver's side of the carb, there's a piece of hose coming out of a tube. Bigger than a vacuum line but smaller than a heater hose. This hose is maybe 4" long and goes to some kind of gizmo that has another hose the same size leading back into the bottom of the carb somewhere and a couple other regular size vacuum lines leading to the carbon canister and elsewhere. Whatever. Anyway, there's a poiwerful suction coming from that 4" hose. It was plugged by the previous owner and when I remove the plug and hook it back where it's supposed to be on the carb, the engine can be forced to start but is REALLY rough and won't really run. So I've re-plugged it and sealed it well. The tube where this goes into the carb is open and unsealed. I can't feel pressure or vacuum here.
But this is kind of a sideline and I don't think has much to do with the basic problem.
Like I said, sometimes it purrs along for a week without any problems at all.

So, after reading my novela here, anyone care to tell me how easy and cheap this is to fix?
:P

TIA Kevin