Hi.
I have a pathfinder I picked up cheap and I am trying to diagnose this problem. When it starts up cold it will start ok and idle fine but if you try to rev it up at all it just stumbles and losses rpm instead of gaining. So far I have cleaned the Maf, replaced the ECT sensor, threw in some other injectors and fuel pressure regulator and adjusted the TPS. It has around 43 psi fuel pressure hen idling and drops to 35 psi when shutoff. The fuel filter is new as well as the plugs. After it warms up it runs great. Trans shifts good and has decent power every now and then it will stumble at full throttle... but only sometimes usually it runs absolutely great after the initial cold stumble goes away. Seems like it is running rich from the look of the plugs I took out when I got it home.
What else should I be looking at?
I am at a bit of a loss as this only occurs when cold. No codes coming up