I put in a gt-40 ford crate engine in my fox body...all my mods are listed in my name....My check engine light comes on once and awhile and then shuts off...I read the codes and i need a o2 sensor and a egr sensor......at low rpms my mustang bucks around until i get back on the gas is this is sensors messing everything up? i have my fuel pressure set at 50 to make it run smoother otherwise it is bucky at certain times..what can be causing this? when i got it dynoed they told me to put the fuel pressure up to make it run smoother..i know it should be around 30 for fuel pressure..any suggestions?