Haven't piped in in a long while...this looks like a good place!

Use soapy water in a spray bottle and look for vacuum leaks. Particularly around the intake manifold gasket/base of the carb...but anywhere there's a vacuum line or potential leak (brake booster line).

Compression/leak down test all 4 cylinders. The 2.6 in particular likes to crack/warp heads (kinda plays into both jet valves and overheating issues).

Check brake lines and consider rebuilding/replacing the Master Cylinder.