Toyota sputters going uphill on the highway

I have an '86 Toyota pickup that sputters badly when I’m going uphills. Even the slightest hill will cause it to sputter. The engine will rev just fine when I take it out of gear, but as soon as I put it back in gear it sputters. I’ve had the clutch replaced, plugs, cap, rotor, and wires. Can anyone suggest some diagnostics before I start start replacing more parts and losing more money?

How about the fuel filter??

How is the fuel pressure? Sounds like you’ve covered the ignition, what about fuel? When was the last time the fuel filter was replaced?

Seems that the fuel filter fixed it for now. Thanks for the reply. I was dreading having to work on the carb. Thanks again.