I recently swapped a brand new motor into my 95’ pickup. Got it running pretty good but there are some issues I cannot seem to figure out I have…
-made sure to set accurate timing
-bench OHM tested my tpms
-cleaned the throttle body
(all parts from the last engine)
it has a brand new intake plenum aswell so it isn’t dirty
the intake and exhaust system I smoke tested and no leaks thanks to all new vacuum hoses

the problem is on WARM starts ONLY it will start and then settle at 500RPM; running rough at idle. it will then be terribly sluggish when slowly getting on the accelerator peddle all the way up to 3200-3500RPM then it will take off like there was never an issue.
also if I press on the gas peddle more than half way it will no longer climb in RPM at all and it will start sputtering like it is almost choking on fuel.

when I start the truck COLD, I let the rpm settle and can drive it with no problem, it’s only when I turn the truck off and back on shortly after

The only other information I have is that
I have a check engine light on for a knock sensor
-code 52
-Knock Sensor Signal - Open or Short in Knock Sensor Signal
i have some ideas however would like some input, thank you.

 

Well I mean, the knock sensor seems like your problem. I don`t know much about the knock sensor, but I believe it is there to adjust your timing if it detects knocks. And probably the ECU does not do anything with the knock sensor until engine is warm. I think I would check first that you have the knock sensor plugged in, perhaps it never got plugged in when you swapped engines or maybe it just came loose. If it is properly connected, then search online or check the FSM for test procedure see if you can determine if your sensor is bad.