Idle/Acceleration problems

[Hailzent47]

So this started out of nowhere on a hot day. I was at a red light when my rpms started going up and down periodically between 1rpm and down to around half. Light changes, I give it gas and the car barely moves. Then suddenly jerks forward and gains speed up until I hit 40 mph when the car momentarily loses power before accelerating again. Car sounds forced as hell. All of this happens when the engine is warm. Car struggles to turn on in the mornings but drives with no issues.

I've had the fuel pump replaced, 02 sensors replaced, intake boot and hoses replaced, and camshaft position sensor replaced. I need some help!!

[Hailzent47]

Also, code reads engine running lean in bank 1.

[EdBwoy]

Well, what was the Pxxxx code? And which car, year, engine is this?
EDIT:
I'll assume it's the 07 M35 in your profile. For some reason, I couldn't see that in your profile when I first posted.
It helps to add that info in your post, or better yet, in the title even if your profile says one thing - many reasons.

Regarding the camshaft sensor:
(There usually is confusion to the correct location/ number required in the V8)
What led to the decision to replace it? Do you know where the replacement part was sourced?

[Hailzent47]

My apologies, it's my first time posting. Yeah I have a 2007 m35 v6. Code that comes up is P0171. Every time something gets replaced, car runs great for a few hours before returning to its previous state. Its dangerous because at times the car will lag to pick up speed while turning at intersections. The crankshaft position sensor was replaced because the mechanic thought that would fix the problem of the car struggling to turn on. I've been told it might be a faulty fuel pump.

[EdBwoy]

No problem, there's always a learning curve.

Searching through historical posts here, It could be as simple as a tear in the intake tube or a MAF.
P0171 (bank 1) is usually a complement of P0174 (bank 2). The V6 bank 1 is the right/ US passenger side of the engine.

Here is a sampling of p0171 threads:
1. post6747598.html?hilit=P0171#p6747598
2. post6611779.html#p6611779

In the event it's your MAF sensor, here is how you test it:
post6772150.html?hilit=maf#p6772150

Those are some of the documented ones, but this is the list of possible causes from the manual:

• Intake air leaks
• A/F sensor 1
• Fuel injector
• Exhaust gas leaks
• Incorrect fuel pressure
• Lack of fuel
• Mass air flow sensor
• Incorrect PCV hose connection

[Hailzent47]

Thank you. I will update with any progress.

[Sstupid]

This is almost definitely a vacuum leak.