P0300 - /PO730

Question

engine runs great no sighn of missfire felt when going 55mph or higher in D check enginelight starts fashing then goes off for afew minutes then returns and the engie rpms. increase and the trans seems to shift down to 3 gear then I shift the fear lever to 3 the rpms come down to normal for 3 gear at 55mph this happens at about 8 miles of driving at normal operating temps. This seems to be intermitent, if I drive with a light gas pedal at 50 to 54mph I could drive for several days with nothing happening.