My trucks idle is a little weird well to me it is it will when I am driving it does nothing out of the normal but if I am at a red light the rpm with bounce between 600rpm to 800rpm

 

4 things are usually the culprit for idle issues, HVAC, TPS or IAC.

Sometimes it could also be a vacuum leak or PCV valve.


Check to see if the erratic idle happens when the HVAC compressor kicks on and off. If that's the case then you're probably low on refrigerant.

Murphy's law can apply if you're lucky enough and it's a combination of these problems.

 

For me it was the PCV valve. Check the rubber elbows. Here's what mine looked like before replacing it. Think it was like $10 on Ebay. Took about 15 mins to replace. The back side by the firewall was a PIA to get to, but overall easy to replace.

 

Ok I will take a look at it this weekend. Cause I don't have a cel or any codes

 

Don't know if it's the case for you, but mine didn't throw a code when I found the hole in the PCV.


Monday I had a P0232 come up at 9.30am. I had a scan ran again to verify at 4.40pm and there was no code. My truck apparently has a mind of it's own.

 

Or you trained it to fix itself?

 

Check if all brake lights are working. The PCM is using the Brake Pedal Position Sensor. It will idle a little higher when your foot is on the brake.

 

Wish it was that easy! She's still at my mechanic's shop. I haven't heard from him yet.

 

Hell yes it is. I was thinking when I had my throttle body off that I should have replaced it. However, it was so damn cold when I did it that "the boys" were had taken cover. Mine hadn't gone all the way through yet, but it is most definitely deteriorated.

 

Since you have a 4.6, I'd remove the IAC valve and clean it with a good cleaner like Berrymans B12 or other brand. Stick it back on and you will probably see a smoother idle and less up and down RPM changes. The v8's air setup will tend to get the AIC to become sticky, if it isn't cleaned regularly, or your fuel hasn't been treated with cleaners. The insides ports get black with residue, and can cause this fluxing of RPMs. Also, the inside the throttle body has a couple very very tiny air ports, that can become clogged if not cleaned also. If your butterfly is opened, and it is black as night inside, then it needs cleaning. These two ports help with the mixing of the air with fuel correctly. B12 will clean this kind of build up without much problem. I'd certainly start there, where there is no cost involved. If that isn't the problem, you can move on.

Just a couple ideas for your problem.