hey guys something i have noticed for a while now but havent really thought much of it till today. when ill be pulling out of a drive way or driving real slow and coming to a stop my truck idles down to the lower 400 rpm range then goes back up to 600ish rpm. cant think of anything that would cause this. it does it no matter if the engine is cold or hot. i replaced spark plugs, wires, and fuel filter about 20k miles ago and im always changing my oil every 3k miles. the only things done to the truck where the cai and two magnaflows and i replaced my old 105 amp alternator to a 145 amp one. and alternator is charging fine and maintains proper voltage (14.05 volts at idle no loads and similiar with brights on and blower at high.) if you need more info let me know!

 

Dirty IAC or EGR or MAF
EGR is doubtful though typically they just hang up and the 3 I inspected this week appeared to be functioning properly to me.
TPS can be out of wack if you fooled with it but generally those are fine as well,as long as you didn't fool with it.
Also did you make adjustments since installing the CAI that could defiantly be an issue as well.

 

clean MAF and TB and undo the battery to reset the pcm

 

2003 had electronic throttle.. Take the TB off and clean it real good.. see if that fixs it.

 

Yep, most likely a dirty TB. I use a old toothbrush, unhook it and remove it to clean it.

 

This cleared up mine which is also an 03. At first it may be worse when you start it up after resetting the pcm but let it relearn the crank position and you'll be good. Also make sure your battery is good/clean/sized correctly.

 

The only way to relearn crank position is with a CPS Relearn via tuning software or a tech II. What has to be relearned after a reset is the idle trims and short term fuel trims.

 

You're right you do need a scan tool I forgot. And now that i recall I only had to do it because my ignition was on when my battery drained so in this case you wouldn't have to.

 

Not hack jack in but This good to know I changed three throttle body on mine and it still does it.

 

my truck has no egr, come to think of it i bet its that MAF since the air filter came oiled and i recently took the throttle body and i noticed it was kinda slick. gonna clean it tomorrow and unhook the battery for a bit. thanks guys! ill let yall know how it goes