My 1978 308 GTB has been in the shop for more than a month. Here's my problem : "When I accelerate and hit rpms of 1000 to 4000 rpm, the acceleration is quite smooth. However, when I accelerate and hit rpms of 4100 to 4500, then I feel that the throttle is slightly suffocated, then some backfires can be felt and heard. Everything has been fixed and adjusted by professional mechanics : the cam belt timings, the distributor settings, the carburator settings. My fuel filter is new, my gas tank has also been cleaned and emptied. Can the fuel pump be causing this fuel starvation at 4100 to 4500 rpm? Do you think my MSD ignition has any effect on the fuel management since my tachometer doesn't work since the MSD was installed ? Is there any connection with the MSD and the fuel management ?