Stalling issues P0171

[Ronin]

Hi guys,

Hope anyone can help me diagnosis this or may have had similar issues on a 3.4L. I can get the car to start but the RPMs are erratic and when you try to give it gas it bogs down and then the car dies. It has thrown 1 check engine code which is P0171.

I have done the following to try and correct the issue

Replaced MAF
Removed throttle body and cleaned IAC
Replaced vacuum lines from PCV to throttle body, vacuum line from intake tube to back of block
Replaced fuel filter
Checked fuel pressure came in @ 42PSI
Also, the TPS sensor was replaced ~6 months ago

I am not sure where to go from here any help is greatly appreciated.

Thanks

 

[Ronin]

Bump, any ideas?

Thinking it may be a bad fuel pressure regulator I swapped this out as well and still having the same issue.

thanks

 

[hambob]

How the RPM's? Low or high? Did this happen all of a sudden? Could be your injectors or spark. More info would help

 

[EatonKyleH]

Where about in Colorado are you? I'd be happy to help you if you happen to be anywhere nearby.

 

[Ronin]

Hey thanks for the offer that is really cool of you, I am in Firestone typically not close to anyone...

So, here is something interesting that happened yesterday. After messing around with the truck again. Started it and it back fired upon start up, now the idle is holding at ~1,000 rpm which is slightly high but the vehicle now will drive but at full throttle it is acting like it is only getting 30-50% throttle. Do you think it could be a bad cat? Tomorrow after work I think I may disconnect it and see how it reacts.