I have an 03 max with 137k. Recently I have noticed that the car feels sluggish... The only problem that i notice is a cover on the catalytic converter which is loose. The noise is a rattling sound, can this piece assist in lost in power?

 

the cat converter cover is just a heat shield and will not aid in power gain. It could be a clogged cat, coils, plugs, MAF, KS, and many more different things. If you don't have a code it will be hard to know exactly what it is without testing those components.

 

Agreed, usually its the cats are clogged, and when was the last time you changed the spark plugs...

 

no codes and i havent changed my plugs for abut 3 years.. car starts perfect tho... i know it will be hard too figure out what it might be.... this suck... come back max!

 

Not to thread jack but I'm having the same issue...

Plugs are 3000miles old and have gutted cats...

Seems like after I let it idle for awhile and take off is where I feel the lose of power... Maybe hear soaked mani??

 

^^^ I'm with you ^^^

I own two 5.5's and neither of which seem as 'peppy' as my 4th gen was. Granted my 5.5's are autos and my 4th was a manual. I just wish I could get it to go like it's supposed to without adding a whole helluva lot of aftermarket gear. With 255 hp, it should scoot better than it is.

I've done the plugs in both, and it breathes fine. I'm interested to know what could help as well. Guess I'll have to trace down and test all the known culprits.

 

Check compression on motor.

 

Do you have a custom air intake?

 

Here is something that you may want to check...

http://forums.maxima.org/5th-generat...esistance.html

 

No intake... Just intake hack... (cutting the intake filter holder)

IAT is a good place to start

 

if plugs are new and IAT comes out good check your fuel filter. I know my 4th gen ran great and i noticed a slow power loss then came idle issues and hesitation after changing the plugs and still having the same problem i changed the fuel filter. it was so clogged that i couldnt blow air threw it. after a new one which was only like 10 bucks it gained everything back. may be something to check out

 

With my 03, I just did the engine swap for a 04 and my power was nowhere barely chirp the tires, no codes came up but when I went to Nissan they said my MAF sensor was bad...didnt get a chance to switch it before my car was totaled...GL to all...

 

My first guess would be clogging precats. Swapping out mine dropped my 45-85 time by nearly 3 seconds.

The 6MT 5.5 gen I had still had the original plugs in it when I changed them at 159k miles and even with the old plugs it still pulled pretty hard.

 

but without any codes where do you start searching?