My problem was described in this thread.

http://forums.maxima.org/showthread.php?t=480283

Thanks for the help everyone. I installed a Walbro tonight, took care of all my problems. The tune looks perfect now.

For future reference, the stock 4th gen fuel pump can handle 260-270whp N/A. (I am not sure exactly where I am at now).

 

So can I upgrade to this fuel pump now and be safe for when the 3.5 is making that kind of power or should I wait until the 4th gen istock pump is maxed out. WOuld only like to dyno tune one time.

 

Glad to hear you got it worked out. Which walbro did you go with?

 

I went with the 255lph walbro, just in case I decide to upgrade further.

 

Low or high pressure? And what's the a/f looking like during closed loop?

 

Kewl... good to know. Glad you got it straightened out. Now get thee to the track man and chase SR and Jime!

 

its the gss342 high pressure. The car has adjusted fine during closed loop, around 14.7:1 same as before.

 

What mods exactly do u have to get ur car to 260-270 ?

 

Here's a good start.

http://forums.maxima.org/showthread.php?t=467517
http://forums.maxima.org/showthread.php?t=462869
http://forums.maxima.org/showthread.php?t=465133

 

How many miles were on the stock pump?

 

About 50,000 miles ago, my speedometer quit working for a while, maybe 10,000 miles, but my odometer shows 17x,000miles now. So the stock pump lasted maybe 180,000 miles.

it could be old age that killed it, but it seemed to work fine until I made some changes to the car and it just could not keep up. At higher rpms the pressure would start falling.