Have had check engine cleared several times, but keeps coming back on. Also has rough idle. Runs fine on the road

 

mark may chime in as he is reading also
any how whats the code

 

Dont clear it, pull the code and post it and we can try to help from there

In the meantime, have you had your intake off recently? Or worked on or near the valve cover? If so a very quick check will be to look at the two small vacuum lines that run to the metal formed lines (connected together with a bracket) sitting right under where the intake tube connects to the manifold. It is very common for someone to accidentally knock one of those two lines off when working on the car and cause a vacuum leak. That would set a code and could also cause a slightly rough idle.