Doug Scovil became OC in 1976. That was the year Gifford Nielsen was an all American and our first 3k yard passer throwing for 3192.

In 1977 G. Nielsen was out for the season after the 4th game of the year. In just 4 games he finished with 1167 yards and 16 tds.
Then, Marc Wilson started the last 7 games of the year and threw for 2418 yards.
The two combined threw for 3585 yards that year.

1978. According to cougarstats.com, Wally English was the new OC. And passing numbers dropped significantly. We did finish 9-4 and won the WAC. Marc Wilson started the year and had 7 int's and only 1 td in the first 2 games! Then Wilson and McMahon split time and neither played well. For the year, they finished with just 2806 yards passing 14 tds and 21 int's. And, a 50.8% completion percentage.

1979. Doug Scovil is back as OC and we go undefeated through the regular season with a close loss to Indiana in the bowl game. Marc Wilson is an All American and throws for 3720 yards breaking many records.

Doug Scovil is OC in 1980 when Jim McMahon has his record setting year.

From 1981 to 1995 Roger French is listed as OC. From 1996 to 1999, Norm Chow and Roger French are listed as OC.

So, what happened in 1978? Why did he leave for 1 year, then come back?