91 Deville spitting and sputering

i have a 1991 deville it idles fine and runs fine til your on the highway and step and the peddle fast then it hesitaes and misses like it's outta gas. any help please

Possibly a fuel pressure issue involving a clogged filter, bad fuel pressure regulator or fuel pump. Check the pressure at the fuel rail before changing parts.

Possibly a fuel pressure issue involving a clogged filter, bad fuel pressure regulator or fuel pump. Check the pressure at the fuel rail before changing parts.

Thanks alot for the info will check it out.

My 4.9 did that, and it just needed a tune-up. If you are due for one, some new plugs, wires and distributer cap and rotor make a big difference!