chr9570

I have noticed a very big loss of power over the past couple months. I bought my 2000 Maxima SE used last year, and after a little while, I noticed a pinging noise at times with acceleration. I thought it may have been bad gas, and have tried every combination of higher and lower octane to try to sdolve this problem. Eventually, I noticed that I had lossed more and more power in higher rpms, and now it seems have almost nothing when it is above 4000 rpms. I have just installed a y-pipe, high flow cat, and a frankencar catback exhaust. This seemed to help a little bit, but it still does not have the power it should have. It feels like a Neon instaed of a Maxima. Does anywone know what would cuase this to happen? I am assuming that it is fuel related, but I do not know where to begin.

NYPD-Arnold

iTrader: (8)

Dirty MAF, maybe?

Progress

iTrader: (26)

Most definitely. It's probably blown. You will most likely need/be interested in a new one. I had the same exact symptoms and after I replaced mine it was good as new.

sloppymax

iTrader: (8)

few questions- can you hear the vias activate at around 5k rpms? have you ever received an ses light? the reason i ask is many of the power valves in the variable intakes are breaking up along with the high failure of coils on 2k and early 2k1s.

Y2K1JKSE

yup...could be that you have a broken VIAS. pop your hood and rev the car up past 5000K...if you see the actuator arm moving then you know that that part is still working. there have been cases on the forum (i forget who's car) that the actuator arm worked but the actual VIAS inside the intake manifold was broken and so he got no high end power.

check that out and if it doesnt work then you know you have a broken VIAS...if it still works and you still feel loss of power past 4000K then you might want to take a look at the power valves.

Kiosk

clean your MAF before u replace it.....

Larrio

iTrader: (10)

visually inspecting the VIAS from the outside is worthless. It is most likely 80% your VIAS malfunctioning due to the stupid power valve design

MaximaPolak

iTrader: (9)

Clean the MAF...there are like 40 threads about that lately...."loss of power after 4000 RPM"

ChromeSE5

iTrader: (3)

bastard VIAS...
The visual inspection is poo poo like Larrio said. The way I figured out it wasn't working was a two step process.
- Unplug all the wires and hoses to the VIAS box. If the car feels the same, then remove the VIAS box.
To do that, you need to
1. Take off your intake
2. Remove or at least unbolt the TB
3. Use an impact driver or some type of pulsating drill on four screws. You can't really use a screw driver because it is really soft metal.
4. When you remove it, watch for a spring to pop out.
5. Look inside and turn the actuator valve. If the valve is turning and a metal brass cup isn't, then definitly your VIAS is broken.
6. If broken, wait for someone to make a fix for it or be creative.