ezzigsxr750

Ok, hopefully someone out there can help me. My wife was driving my 2004 F150 (4.6) and the battery died. I jumped it and drove it home. I tried to have the battery charged but it wouldn’t hold a change so I got a new one. The check engine light then turned on. After that the trucks idle started surging when I would slow to a stop. Shortly after that the truck started stalling when I stopped. It happens more frequently when the A/C is running. I tried to get the code for the check engine light but autozone said there is no code. I Looked at her like she was stupid so I went straight to discount auto to get it checked their and he said the same thing, that there was no code or that the computer could not be picked up/read. Someone please help me. I am completely lost and can not find the answer anywhere. I have found these exact symptoms (including the battery change) on other posts but never any answers.

Thank you, -Bobby

Good old Bill

Reassurance is in order right now. Battery crashed and drained all the life out of everything. New battery and now check engine lite, am I correct? If a reliable volt meter is available check voltage with engine off, record. Start engine and read voltage, record. Start engine and run up to 1500 RPM, now turn on stuff, radio, AC, lites and record voltage. Very good, you can follow intructions, you Putts. Sorry, one or two many beer manuals, any way what I'm trying to find out is the integraty of the alternator. Would like to see similiar readings with engine on and at 1500 with the stuff turned on as it was with just the engine running, both should be above engine off battery voltage. Back to the wierd engine symptoms, probably the computor needs to relearn its idle strategy. Normal driving can do this, but sometimes its best to help it along. Am going to let someone else take you through the idle learning strategy. If there is no CEL activity, and the alternator is providing more voltage with everything on versus engine off battery voltage, you should be good to go.

tschneider4x4

This scenario is like dejavu for me. Last October my battery died, so I installed a new one...of course, then is started surging at idle and would die on me while stopped or even in slow turns sometimes.

I don't know if the PCM relearned my driving style over time and caused it to resolve itself. Possibly other parts had worn to where the factory default program would run well without relearning the parameters related to my driving style and engine condition...sounds good anyway

The only other thing I can think of was that I did replace the fuel filter around the time when I started to notice it running right again. Not a huge expense or amount of time to replace it, so probably wouldn't hurt if haven't done so recently.

Actually, I just thought of another thing I did after reading deeper into my manual. There is a relearning procedure in there where you disconnect the battery for a decent amount of time to, idle for so long, and then drive at verying speeds for a while prior to driving the truck "normally". I don't remember the specifics of the steps, but your manual has it near the changing the battery topic. Hopefully this helps. Definitely let us know.

Good luck!

T

rplatt56

Yes the PCM must relearn again. It will resolve itself soon

ezzigsxr750

Well yesterday I checked the alternator and it was fine. I did get to thinking that maybe for some odd reason it could be some crazy fuse that is blown. so i went a checking and found that my cig lighter/computer port fuse was blown. so i quickly ran to the local auto parts store and replaced the fuse and had them read the check engine code. It came back with PO506-unexpected low idle intake air. I changed the air filter and still the same problem proceeds. Does this have anything to do with the relearning procedure or does anyone have or know where i can find that relearning procedure? Thank you

Blackotteroutfitters

It is definitely the idle and fuel trim relearning process. The best way to fix is to disconnect the battery again. This time when you reconnect. start the truck (before you drive it anywhere!!!) let it idle for 10 min. then turn the ac on and let it idle for a few more minutes. Then drive it normally for 10 min or so. This is the only way it will relearn the idle correctly.

munoz2105

Same problem here. Did the procedures from the owners manual worked?

sbridges65

Hello, I'm also having the same problem with my o4 5.4 after repairing my alternator. I.e. low idle and occasional stalling. Thanks for the info. Duhh, I didn't even think to look in my owners manual. Thanks for the info. Great forum!!!



-Sbridges65
Ford Rules!!!

ProZach

ok so I was having a problem with my truck similar to this but different mechanics said different things. One cleaned the MAF and the other cleaned the throttle body, neither worked. Then I read this thread and did as the manual said. Here's what happened.
disconnected the negativ cable on the battery for 10 minutes.
reconnected and started the truck with all accessories turned off.
truck rough idled for 20 seconds then stalled.
started it again and serice wrench comes on.
let it idle with nothing on and no more stalling for 2 and half minutes.
then let it idle with a/c on for 2.5 minutes.
drove around for 10 miles with a/c and radio on and then pulled over and shut it off. (the whole time the ac was blowing hot and it was 104 out.)
started back up with still hot ac and now service wrench and check engine light.
drove it the rest of the way home and game up for now.
Any ideas? should i do it again? start over the whole process?

VaF150

I have an 07 F150 Lariat that I just bought a couple weeks ago and noticed rough idle when the a/c is on but doesn't do it when the a/c is not running......Could this be the same issue with mine? No engine light has come on so don't think I will have a code.........