90 350 tbi running poorly

I have a 90 GMC with a tbi 350. For about three weeks it has been running poorly especially when it is cold. It starts up every time but will sometimes die when idling. When I take off it will surge really bad at least thru second gear, then not having any power after that. Usually when the temp comes up it wont surge but dosent always have much power. It will sometimes try to die or will die when I step on the clutch to either stop or slow down to turn a corner. I have replaced the spark plugs, wires, cap, rotor, pcv valve, egr valve, fuel filter, and map sensor. I am running out of ideas. Anyone have any? Thanks.

Check all vacuum hoses for leaks. It would help to get it scanned to see what the sensor are reporting especially the engine coolant temp (ECT) sensor. If the ECT sensor is wrong, cold performance and even warm performance can be affected.

Fuel pressure also needs to be tested but requires a special tool. Should be 9 to 13 PSI.

Has O2 sensor ever been replaced?

//2000CAYukon

Thanks for the response. I had looked over the hoses and didnt find any leaks. Will do the pressure test this weekend. I havnt changed the o2 sensor.