In 2001 Mienke replaced the muffler on my '90 Maxima (automatic). I just had that muffler replaced 2 weeks ago BUT - the muffler sounds loud; like a muscle car, sort of a weak muscle car; it rumbles when idling and at low speeds up to about 30mph. Also, in the morning, as I get up to highway speed (about 60 mph), it seems to take about 12 miles before the final phase of 3rd gear kicks in now. I can tell that by the sound, and the tach thing which usually runs at 2 when I am at 60 mph, but now runs around 2.3 until that final something happens. And finally, on acceleration up a hill, the car is a bit sluggish now, post muffler installation (and to be honest for the last month or two when I needed to get the muffler replaced).
My questions - are mufflers sometimes bad from the start? Could Mieneke have installed a bad muffler? What else could be making the muffler be noisy? Could the muffler be the cause of the sluggish acceleration? What might be causing the car to take so long to settle into final phase of gear at highway speed in the morning?
Thanks for your help! It may be obvious - I don't know that much about cars, but if you can guide me with simple explanations or things I might ask the Mieneke person about. Thank you!