Plz help!

I have a nissan sentra 96 gxe that loses electrical power during exceleration. When you step on the gases pedal the interior lights would dim and if you keep you feet on the gas it would dim so much that the car will loses power and slowly start to die. But if you let your feet off the gas the power seems to come back. I can no longer go past 60. This all seem to happen after I got the muffler and exhaust pipe replaced. Can it be spark plug? Fuel pump?

sounds like altenator or a harness issue. with the car idling pull on the wireing around the altenator and the battery see if it dies. I suspect this only really happens at night. It does not sound like a drivability issue but and electrical problem.