Pulling a train

When I get in the van in the morning, it starts up a takes off fine. As soon as it’s warmed up it will not accelerate from a standing start. It crawls extremely slow until it reaches 20mph, then it kicks in and drives normal. God forbid I stop on a hill the world thinks I’m being a @$$hole. The code reader says it needed oxygen sensors, so I spent $350 for four new ones. That didn’t work. I changed the fuel filter, that didn’t work. I know you have to be a mechanic to own an older car, but I’m not one.:banghead:

Welcome to AF, lets start with the year and engine, please?

96 Savana 3500 5.7

Try a torque convertor stall speed test, brake on hard in drive, bring the engine up till the truck creeps, with a tach or scanner it should have about 1400-1500 rpms, if not the engine could be out of time, the t. conv. could be bad, or the engine down on power for a number of reasons, also have a full scan done.