hey, i recently purchased a 1992 honda civic lx. (eg8) it has a d15b7 engine but it dies when i come to a stoplight. ive cleaned the iacv and throttle body. the motor was professionally rebuilt 100 miles ago. but for some reason when clutch pedal is pressed the rpm drops to about 400 and the engine dies. what could be the cause?

 

Any CEL codes? If not, make sure the PCV valve is working, and then adjust the base idle speed to 420 rpms using an external tachometer.