I’ve got a 1990 pickup 5 speed with 271k on it and recently it started losing throttle response when I get to about 55mph. As soon as it slows down to about 50 mph the throttle response picks right back up like nothing happened. If I put the clutch in when it has its hissy fit it will die. In the past it has thrown codes 24 and 41. It also has picked up a high idle. Everything I have read says that’s typically a vacuum line but I have checked all the ones that I can find and everything seems to be good. No cracked lines and seem to fit snug. Tonight I pulled the throttle body off and cleaned it. I have replaced the throttle position sensor (adjusted it to specs), the mass air flow sensor, has a new fuel pump and filter also. I have also ran all the wiring for the TPS circuit out all the way to the ECM. And they ohmed out. I’m just running out of ideas on what could be causing the throttle loss and what to check. Any help would be appreciated!

That would make sense if it’s cutting the fuel off why it dies when I put the clutch in. I wonder if there is something that piggy backs off the throttle cable that goes to the ecm that could be throwing it out of wack.