2000 gt mustang. I just rebuilt this motor for a friend. It was down for two months. The motor came out of a 2002 gt that I rebuilt. I rebuilt it stock, the only mods are a bbk 70mm throttle body and a CAI. The motor that came out of the 00 gt was to far gone to rebuild, but the throttle body and the CAI were on the car already before it blew up. Does it need a tune now. I'm thinking that it possibly had a tune before, but having the battery out for two months reset the computer. It is giving me codes p0171 and p0174

 

Welcome

 

Thank you

 

Welcome! Post in the 4.6 section of MF. GL!

 

The car idles fine in park, but the minute I put it in drive it wants to stall out and does stall.LTFT1 is -0.8 to 1.6 %. LTFT2 17.2 to 21%

 

I had a F150 that would do that. See if you can pull a code it might be your IAC

 

Welcome, glad to have you.

Verify all vacuum lines are connected. Your symptoms point to unmetered air getting in and the computer can't adjust accordingly.

Also, these type of Tech questions should go in the Tech Section, just to keep the forum organized. Good luck

 

Welcome & Happy restoring your Mustang !

 

Welcome to MF. Check for vacuum leaks. Check the maf, and clean it.

 

I changed bank 2 sensor 1 o2 sensor and it got a lot better and I put the stock throttle body back on. Now it runs fine. The only time there is an issue is when at a stop and the brakes are applied it wants to stall out. If I'm stopped in gear with the parking brake on it idles fine the minute I press the brakes the idle drops out. So definitely thinking a vacuum leak but just cant find one. Any ideas would help.