My 2000 Maxima SE has recently encountered major power loss and acts very strange when I try to floor the gas pedal.

When I try to floor the pedal, the tach pegs at about 4k rpm's and kind of flutters there and won't go any higher. If I don't floor it, I can gradually climb to over 4k rpm's.

I recently had to replace the muffler. The replacement muffler isn't the two stage oem type that opens a flap at 2k rpm's, this is just a single pipe muffler. The muffler shop said this would not hurt performance; it would only make it slightly louder at low rpm's than the oem muffler (Is this true)?

I just changed the spark plugs(they needed it regardless) and noticed that two of them smelled like unburnt fuel and the rest of them had no scent at all.

I did not replace the ignition coils as I have no reason to believe that they are failing.

Does anyone have any ideas or suggestions here?

My car has 150k miles on it but they are all HWY miles. I commute about 700 miles per week.

Thanks for any input.

New info!

After reading more threads here I decided to take the car to Autozone and have them check for service codes. My ses light is not on BUT I had three codes.

P0171 -- MAF
P0304 -- Cylinder 4 misfiring
P1320 -- Ignotion coils in general

I've already replaced the sparkplugs. How can I tell which is cylinder 4 in order to replace the correct ignition coil?

 

MAF sensor!!!!! Replace it it!!!! You can get it at www.jerryromenissan.com. When ordering use the promotional code "maxima" to get a 12% discount. It should be around $95 shipped.

Part # 22680-2Y001

 

probably the MAF, it's very easy to replace. I had the same problem

 

My first bet would be to replace the Maf. I had to replace mine and it fixed my power loss problem and it is a very simple replacement. Good Luck!