My car is a 91 tpi 350. Ever since I bought the car it would always run it's *** off in open loop,but as soon as closed loop took over then it would feel a little hesitant.. This only occurs under normal driving conditions, such as driving my car in drive position and letting it shift under normal throttle. When it shifts into second or third gear then it feels real sluggish. Almost like a 5 speed car that is being shifted from 1 st gear to 4 th! WTF? However, it still runs fine under WOT and runs great regardless when I am below and 1/8th of a tank. Runs like normal then. Fuel issue? Well, I have replaced distributor cap,rotor, fuel filter, fuel injectors, fuel pressure regulator. Not because of this problem of course.LOL but I am kind of leaning toward this maybe being a timing issue also? Any thoughts or ideas would be appreciated.