Stumble off idle, disappears when map sensor is disconnected

[coffeeguy]

95 TBI idles fine but stumbles when accelerating , then run ok ( but poor fuel millage). When the vacuum was disconnected it idled higher but the stumble went away ad it ran fine? Swapped Map sensors and same results. Any ideas?

 

[Eman85]

I'll play, which is all we're doing here with no data. You pulled a vacum hose so you leaned the mixture. My idea is you need to scan for codes and read live data. I also don't think the MAP sensor is the problem.

 

[exp500]

Three biggest problems in order of occurance, Idle air control (clean/reset), Fuel pump, Fuel pressure regulator.
Fuel pump relay if on firewall is also problematic.
Address gas mileage first. Meaning find ignition miss if there, tune up, maybe distributor. A bit of diagnostic snooping in order to narrow focus such as codes and vacuum readings while driving, and vehicle specifics like how many miles? well maintained?
Fixing a 30 year old truck is no longer add a can of injector cleaner.