Hard start when warm
 

I've got a stock 93 LX 5.0 that idles fine and runs fine but when it is at normal operating temp. I have to hold the gas pedal on the floor to get it to fire. Since it idles fine I do not think it is the TPS, I was leaning towards the MAF or O2 sensors.
Looking for some insight on how to troubleshoot this.:confused:
There are no codes in the computer.