engine light came on and ran a scan.It showed egr valve stuck open.Replaced egr and cleared code.Drove about 4-5 miles and light came back on.My friend who is mechanic ran tests with his computer.It showed everything was working properly.It would open on acceleration and close on idle.all systems were running ok.What else would cause the light to come back on with the same code.Any help would be appreciated.
2 weeks ago had to install cam position sensor.
thanks for any help