munoz2105

I changed my spark plugs about 4 months ago and got that erratic idling but it it got a little better after a day or so but still anoyng. So yesterday I had time to re do the spark plugs in case I gaped the plugs wrong. And the plugs were fine but changed them anyway since I took them out. Still same problem just a little better. I turned on my truck again and I get a check engine light. Went to autozone and got a P0506 idle control valve code. We checked and these new f-150s don't have an idle control valve. Unplugged the battery and connected it back and the check engine light went away but it still idles rough under what it should. I read some posts and said it was the throttle position sensor (TPS) and they said to clean it with carburator cleaner and solves the problem but I did that and nothing still have the same problem. Can anyone that's had this problem help me?

Blue Oval 87

I had that problem with me 1987. I changed all the battery cables, battery, starter and solinoid and my idle was rough. I disconnected the battery for 15 mins. Reconnected the battery and let the truck idle in the drive way for 10 -15 mins or so. I then drove it for about 10 mins. The idle problem seems to have gone away. I found out that when the battery is disconnected, the vehicle's computer needs to relearn the engines idle position. They say this is supposed to cure itself over time, but the rough idle was getting on my nerves so this seemed to help. Hope it helps you.

Mod (Ret.)

I'm puzzled.....how is changing all the battery cables, battery, starter and solinoid tied to a rough idle???

I can understand the battery cable disconnect procedure to force the PCM to re-learn, but I don't see the relationship of a starter and solinoid change and rough idle.

grandy185

Whats your trucks vitals? (YEAR MODEL ENGINE) I would get your Coils tested first off...

To answer the question above this post... Your engines computer has the ability to adapt to different conditions... Be it external (climate alttitude) or internal(minor engine probs and wear) when you disconnect power for a period it clears everything the computer has learned about how to run properly under all the giving variables, so it has to slowly relearn... Sorry if that was to tecnical but there it is in a nutshell

munoz2105

Thanks everyone for all your help. I will try the battery thing tomorrow and if that doesn't do it ill just give it time for the pcm to re-learn. Thanks