Car rough idle started after transmission was repaired . Car idle rpm jumps from 8 to 4rpm up and down when the brakes is applied then smooths out. we changed the fuel pump, spark plugs, serviced injectors and nothing helped. Check boaster for leak and worked fine. Serviced the throttle body from the back and still no change in performance. The throttle the body was replaced 2 months before the transmission failed so it is relatively new. If the idle drops to low while coming to a stop when the brakes is applied, the cars stalls. Please help, my mechanic has given up. What to check next?