changed egr valve and o2 sensor and check engine light goes on n off cant insp

Do you have specific trouble code you are dealing with? Sometimes a code can point to a problem such as and egr valve or O2 sensor and what the code really means is that there is a problem with that system. Such as a clogged egr passage or a lean condition as apposed to just a part failure. Would need more information to get you a better answer.