I have a 11 rt 5.7 swapped a 392 cam no.mds vehicle has a 6.1 intake hemifever has tuned it. But driving steady speeds 20-40 i feel a surge of about 50 rpm you can feel it and hear it in the exhaust. Any ideas
Have you done any revisions to the tune since you got it running after the initial start up tune? If not do a data log of the problem area, some normal in traffic driving, and a full throttle run in 2nd or 3rd gear from about 1500 rpm's to red line between 6000 and 6400 rpm's. E-mail that back to Hemifever and he will corrected it or let you know if it is a mechanical issue that needs attention.