does this have a carb,or throttle body?
either way the fuel filter is important,and the air filter.
we had a problem with a few vehicles at work,small birds built nests in the air intake tubes,that go to the air cleaner,
The TBI throttle body units have a fuel pressure regualtor spring that weaken,and sometimes break;
i had to replace the pressure reg spring on my 1990 4.3 v6 chevy pickup,last fall.
i will look for the website that gave good directions..if they weaken u can add a Quarter,under the spring to shim it, if broken, they have to be replaced.
http://www.dstutz.com/caprice/25cent.html one site,good directions,