Engine Oil Leaking problems of the 2008 Ford Focus

2008 Ford Focus does not accelerate properly or stalls randomly. On multiple occasions I was in traffic on both city streets and highways and nearly got hit more than once. I had the pcm replaced by a certified Ford mechanic in 11/14, it had a two year warranty. In 1/16 it began doing the same thing. It had to be replaced in 4/16. After replacing the pcm at a Ford dealership the second time my car stalled out on me the next day. The pcm code was the same at each location (code p00607). Both pcm's were purchased from Ford brand new. I am now being told by the Ford dealership that the following code (p0320) was obtained. They indicated the following work needs to be done in the amount of $575. The cost of the repairs include: tune up is $260. 00 this includes spark plugs ,spark plug boots, and 2 ignition coils and the labor to install them. The cost to replaced the valve cover gasket that is leaking oil into the spark plug valleys is $315. 00 this includes the parts and labor. (spark plug valleys #3 and #4 have oil in them. ) my concern is that this was never a pcm issue; however, it is something else feeding misinformation to the pcm to send inaccurate codes to the entire system. The probability of three pcm¿s being faulty in 1½ year is not likely. This vehicle has stalled in traffic on more than one occasion and is a risk to others and myself on the roads. I have grave concerns regarding the reliability and safety of the 2008 Ford Focus se. Ford needs to investigate and correct this safety issue.