Fire fire crews were called to the fire, just before Junction 3 for Albrighton on the westbound carriageway, before closing off the motorway completely for 15 minutes.
The car blaze was reported at around 8am, with a full closure in place from 8.20am.
Three fire crews from Albrighton and two from Staffordshire Fire and Rescue attended.
The fire crews used breathing apparatus and a hosereel jet to tackle the flames.
A second lane was opened at 8.34am and the area had been fully reopened by 8.50am.
The fire service said that the fire was due to an engine malfunction.