1989 Gmc Sonoma 4.3 Spitting and Sputtering problem.

Ok well this started a couple days ago and I attibuted it to me running through a mudhole because the symptoms are what I used to have but now they have gotten worse and they havnt gone away. Now it will spit and sputer when i give it gas and then it will shut its self off when I go to slow down or stop. Usally it starts right back up. Im not sure on what to do now. I changed the oil and it needed it black as midnight with no moon and it didnt have any water or different smell to it. Next thing is the plugs and wires which I am doing right now. If anyone thinks of anything else please help. Also it didnt give a code when it shut down it acted as if i had just turned the key off. Also on a side note when it doesnt start right back up everything goes down low like the power and everything else

When it quits check for lose of good hot blue spark to all plugs and for lose of fuel pressure.
What is your fuel pressure readings?

could it be a timing issue?