Motor Racing to 3000RPM at idle!?!
 

My dad has a 93festiva L 5sp manual (used to be an auto but we swapped it ((might be relevant?))
Since we swapped in the motor all it does is race/smoke and there very is little braking power.
We switched out the egr valve, and some relays which didn't change anything.
Any suggestions as to what the issue might be? Maybe a computer issue? Intake manifold gasket seal bad? Any thoughts are appreciated. Thanks~

I am not familiar with festivas but a racing motor sounds like it just injesting too much air. Inspect the throttle body linkage, throttle plate sticking, throttle stop screw set incorrectly, or intake air control valve (if it has one) not functioning properly. The brakes are usually helped by the brake booster which uses vacuum assist. If the motor is racing, there is low vacuum which means the brakes don't work well.

Vacuum leak. Not sure if the AT had a vacuum modulator but that would be my first suspect.

regards
Mech