Backround- My 2008 ranger with a 2.3 liter dura tech engine gave up at 249,000. A friend installed a junkyard motor. The truck has a manual transmission, the donor vehicle was an automatic.
Issue- When I start the truck the idle is approx 2500 rpm, when driving the idle seems normal, until I clutch then the idles rises to 2500 or higher instead of dropping off to about 800 which should be normal, It seems like the motor is searching for the automatic trans.
Question- What should I be looking at to try and fix this? The computer in th truck was not changed.