Hello so I have a 1988 chevy 1500 with a 350 in it. I drove it for about 10 minutes the other day no problem would spin the tires over easy also. The next day I drove it to my grandma's no problem. I go to drive home and its like it has a loss of power and wanting to stall. I will be driving and the engine will just randomly act like it wants to die, then be fine. Then it will do it again and if i stop completely it will die. Also when this happens with the engine sputtering I can press on the gas and I will not accellerate but it will keep the engine alive. Please help me
Wow could be a mess of things. It might not even be related to your fuel system either. But, lets start there.
First, lets talk about your fuel quality. If degraded over time will cause the engine to run lousy. Either its running bad all the time, then it is from the gas or if it is not running bad all the time and just has temporary issues, then it is not from the gas itself. If it's not the gas, it can still be an issue in your fuel system, like clogged injectors or clogged fuel filter.
As Lee pointed out, start with the fuel system or fuel injector cleaner because it is the cheapest solution to your problem. However, do not buy the cheapest fuel injector cleaner though because it is ineffective and will not solve your issues.
You want to make sure the fuel system cleaner you use has (2) things:
1) An emulsification agent 2) Is flammable.
An emulsification agent bonds with any moisture or water in your entire fuel system. Chances are, since we are in winter now, your gas ended up getting some moisture in it and this could cause the issues you described.
Next, you are already experiencing running issues so why would you dump anything else in your gas tank that isn't flammable? Be smart here, using the wrong product will not help you. This is the only fuel system cleaner I recommended to use because it is the only one in the world that has an emulsification agent & is flammable: https://www.protecautocare.com/motor-vehicle-care/fuel-injector-cleaner
After you put one can in your tank, try to fire up the vehicle and play with your throttle to keep it idling as you mentioned you had to. After about 10 minutes, the cleaner will have made its way to your motor from the gas tank and you should start to see some improvement in the idle. Now, it's time to go for a drive. You want to "beat on it" or put the pedal to the metal and floor it a few times. That will put a full load on the motor and help to ensure any carbon buildup that could clog injectors has been burned up.
If that solves your problem, then great! If not, as I first mentioned, it might not be coming from your fuel system. Loss of engine compression can have the same effect. There is also an easy and inexpensive way to try and fix this yourself by using the best engine flush available: https://www.protecautocare.com/motor-vehicle-care/engine-flush
This will make sure your engine is free of contamination and fully lubricated with ZDDP. It also helps to restore engine compression and un-stick piston rings. It's safe to use regardless of the age of the vehicle or how many miles it has. You also do not have to worry about contamination breaking free and causing other issues in the motor because this fully dissolves all contamination to smaller than a micron.
After you have done the engine flush, I would then dump a can of oil lubrication booster in the motor to make sure it has some high quality lubrication and protective coating ensuring piston to cylinder gap clearance has been restored, thus increasing your compression and causing the vehicle to run better.
Check that site I linked, they also have a tuneup kit on sale that has all 3 of these products with free shipping.
Best of luck, let us know how it turns out.