I have my 2007 Silverado 5.3 LY5. Finished the cam head swap about 5 weeks ago. Had Justin from Blackbear retune it. It was fine until a few days ago. Now when coming to a stop the idle will go down to 500, jump back uo to 1200, drop down and stall. If I give it throttle it will stay running. I do not have any codes in the ECM or FPCM. MAF and Throttlebody are new. No vacuum leaks.
I made no changes to the truck after the tune. This just started one morning.
Question is, my fuel pressure at idle is 42psi. Spec is 52/62. The desired matches the actual on my Tech2. Is this something that is changed during the re-tune? I put a gauge on the fuel rail and it is 42psi. Seems low. According to what I know fuel pressure should not change under load, should remain constant, right?? My fuel trims are normal and it drives fine on the highway.

I would think the desired would be higher??? Or is my pump going out?

 

Probably want to post this in the GM section...

 

Fuel pump might have ate the dust.

 

Check your injector pulse width, i'll bet it is higher than normal. Plan on changing the fuel pump. Double check the harness at the pump to make sure it is not melted, increasing resistance.

 

Also monitor voltage. Low voltage will cause all kinds of heck.

 

I would think that the fuel pump might be going out because four of my friends own silverado pickups and three of them have had to get a new fuel pump and the one that hasn't had to change his yet has already ordered one because his is starting to spit and sputer. Oh and also i would check the fuel filter.