I have a check engine light and after a scan by the code reader, it shows a code 33. I had checked all the vacuum lines and even switched out the EGR and EGR position sensor from a friends mustang and the code is still there. I even tried the EGR vacuum regulator and that did not help at all. I check the voltages and they seem right. I even left the neg battery cable to try and reset the computer. As soon as I start the car, back comes the check engine and code 33. Can some please help? Thanks.