1998 f150 4.6 to 5.4 swap with 4.6 wires n stuff with custom tune..

i know the tunes not the problem... but my truck when i start it in the cold it will just start leanning out and die...

i have a wideband so i know its leaning out...

im told it is the idle controle or something....


but if i have a bad idle dealo... would it still die when driving?? like if i start the truck and just drive its fine but the second i let off the gas it will die...

its alright once warm...

and another thing i dont think i have this problem any more but my truck was leaning out when wide open... like i was maxing out the fuel system.. but it dont seem to lean out any more...

 

Idle Air Control is what you are referring to. It is what controls the idle speed. Sonds like yours is not working good when cold, but starts to work when warmed up. It is connected right at the throttle body. Has a wire connector and is a couple inches length.

 

try cleaning your IAC or just replacing it

 

Does the iac for a swap need to be the one that was original (4.6) or can it be either the swapped one (5.4) or original? They may have different duty cycles?

 

I think ill clean and hope it works... try to go cheap on this one if I can...

I bet the intake needs to be cleaned any ways

 

They generally dont clean up well. You might get it to work better temporarily..