Without a TPS the ECM won't know when it is supposed to try to control the idle (throttle closed & vehicle not moving) or not. Don't worry about the idle too much until you get the TPS in working.
You prob can get a 2.8 throttle body from the MALL section of this forum for $20 shipped. Here is one on eBay for $25. Have them make sure the screws aren't frozen before you purchase it.
https://www.ebay.com/i/3225...51?chn=ps&dispItem=1Coolant does pass through the throttle body but make it quick and you shouldn't have too much problem with lost coolant. Might be a whole lot easier than trying to get the screws out of aluminum.