So for the past month or so I noticed my 03 Maxima is really sluggish when accelerating. I have to push the gas pedal pretty hard to get it to go. Plus I've been getting poor gas mileage (about 180-190 miles on a full tank) and a very light vibration when idling. I took it to my local Nissan Dealership who is telling me there is nothing wrong with the engine and the issue is actually the ingen intake. I've had the intake installed for a year and there never has been an issue. Could this actually be the issue? The technician said he would recommend getting the OEM intake ($1200 plus installation) in order for them to continue running more tests. Anyone with an ingen intake experiencing this? Any recommendations on what to do?

 

The intake isnt helping since its a power robbing piece of garbage, but its not causing your problem. Its probably your MAF going bad

 

This sounds exactly like my high mileage I35. I'm at about 160k

 

check ur spark plugs and coils dude along with what Gemner said MAF

 

when I replaced lower oil pan car felt better..
poor fuel mileage could be the evap canister and/or valve
maybe the filter on the car is getting dirty? Clean it?

 

I have same exact issue it's not even funny how identical it is , do you any cat codes? I was thinking bad plugs is causing the mpg and power issue

 

No codes. I was thinking the spark plugs as well.

 

Filter is clean. Or do you mean the in cabin filter?

 

I have a little less than 70k.

 

My 03 has 160km and runs like a champ. It puts me back in the seat at half throttle. I lowered it with eibach springs because the torque steer and body roll was crazy. I have had many quick cars but this is a favorite. Unless your engine is shot from lack of oil changes you have a problem and can likely bring it back with the help of this site.

Your ingen intake is probably not the problem. Doesn't seem to be a common one anyways. When I first got my car over a year ago it performed much like yours. I had a real loss of power in the 2.5-3.5 rpm range. Of course the first thing I did was plugs, but I would bet you it is your Mass Air Flow sensor. Very common because they don't last forever and they are not likely to throw a dtc (check engine light).

Spray the maf clean and see if it helps. If so, replace it with a 2001 updated maf that cost me $80 delivered rockauto rather than $350 plus. Plug and play with 02-03. Check pics to ensure it has 5 pins and the thermo resistor. I think almost all of them do now.

There are also many other places to check but the maf is common and takes hardly any time to clean and is the cheapest fix!

 

Does the ingen intake have a dry filter or an oiled filter? If it's an oiled one, your MAF may be damaged from the oil

 

+1 Oiled air filters can eff up your MAF...