More serious as in?

You should sell your Pinto to someone who knows car and get yourself a "RICER".

My buddy swears by Seafoam in his toys that sit a lot. As a last resort try a bottle & see.

I noticed you had another post of white smoke and idle, remember excessive additives can cause that, pintos make awesome learning cars, simple and easy, get a haynes manual or a chiltons and read up, cars are big legos, use the right tools and dont halfa** anything and you will be fine.

now back to your problem, how long was the car sitting before you got it?
might need to drop tank and drain, pour some alchol in it swish and let dry, could of had bad gas and water in tank from sitting, additives only work so much.

next a stumble can be anything, i had bad misses only at one rpm, found out it was the back two plug wires.

do a good tune up on it, clear any questions you have on it, internet is a good source for info.

btw, the only good thing ricers are for is to learn how bad front wheel drive is, and how fast sh** hits the fan when you go fast in a turn

Lol thanks ghost. I still have the issue, replaced spark plugs, wires, ignition coil, starter sullenoid, and alternator.