Possible reasons for floating speed when shifting automatic transmission gears:
1. Faulty sensors:
* Vehicle speed sensor
* Throttle Position Sensor
*Mass air flow sensor
2. Problems with the transmission control module (TCM):
* Faulty TCM
* Bad TCM connections
3. Problems with the torque converter:
* Defective torque converter clutch lock-up
* Worn torque converter
4. Problems with automatic transmission solenoids:
* Faulty shift solenoids
* Clogged or dirty solenoids
5. Low level or contamination of transmission fluid:
* Low fluid levels result in insufficient pressure and gear slippage.
* Contaminated fluid can clog solenoids and valves.
6. Engine problems:
* Faulty ignition
* Faulty intake system
* Clogged fuel injectors
7. Sports driving modes:
*Some vehicles have sport driving modes that increase revs when changing gears to improve acceleration.
Diagnostics:
*Check trouble codes using OBD-II scanner.
* Check the transmission fluid level and condition.
* Test the automatic transmission sensors and solenoids using special diagnostic equipment or contact a qualified mechanic.