Engine shudder, cutting out

[Contibob]

Was driving my Del Rio today after installing a new radiator. It ran great for the most part. After driving for a while I got on it a bit and under load it acted as if it was missing or cutting out. Only when really putting my foot into it. Regular driving smooth as silk.
Weak fuel pump maybe???

[Wirenut]

Dirty fuel filter?

[chapingo17]

Agree.

[Fairlane62]

Yep

[Contibob]

I'll give that a try. Certainly one of the least expensive things to try.

[Fabulous50s]

Next thing I'd look into is ignition. Missing under load is classic weak spark.