check engine light comes on for aday or two then stays off for maybe two weeks 1999 dodge ram 360v8

i'll need to know the diag. code. if you do not know it try this, put the key in the ignition cylinder and trun it to the run position "not start/do not crank engin"and back to the lock position"position where the key comes out". do this 3 times leaving it in the run pos. on the last sweep. in the odometer space you should see a p#### light up then followed by DONE. the p number is the diag. code and done means it's done displaying diag, codes. it may take a few trys to get it down, after that you'll find it easy to get codes

or take it by a auto parts and have them check it free. they will tell the code and what system is sending the code.