Hello everyone so i have had my 86 gts for a lil bit and the other day she died on me . she popped out of gear and then died so perplexed i waited till i cam to a stop and tried to start her and she would fire right up then would not hold an idle at all i tried this multiple times and same result. being a motorcycle tech i thought that the problem might be the TPS but i am not sure can anyone give me some knowledge as tto what it could be. if push comes to shove i am just going to get a new motor to drop in ecu and harness. if i do that does anyone else know if the efi one my motor would work fine or would i need to get a new efi system as well

also what motor would be best and easiest to drop in

Sounds like a vacuum leak to me.

Easiest motor to drop in would be another 16 valve 4A-GE. Motor plus trans is roughly 1200 from an importer.