OK. I changed my spark plugs to the 3923's two weeks ago. It's a new truck with the 4.7L...only 2500 miles on it. I changed them because I had a great expereince with them in my '06 that was traded in last month.

Today, I noticed an idle issue in the new truck that I never experienced with the '06. While sitting in front of the house, it was sitting idle at about 800rpms. Then it dipped way low to about 300 then back to 800 immediately. Just to see if it would do it again, I let it sit another few minutes and back to about 300 and back up to 800. Why would it do this? Bad plug somewhere to make me change all of them again? I have noticed it running slight rougher than normal at idle, but I figured it was the crap weather that may be effecting it. I am at a loss. The plugs were all installed correctly....0.40 gapping and 20 ft lbs of torque. Any ideas????

 

Could be issue with plugs my 05 has done the samething I installed champions runs great could also be bad gas happens throw some injecter cleaner threw it!

 

you did not happen to mess with the throttle posistion sensor at all. when these start to go bad the idle will jump all over the place. even though it is a fairly new rig, it may be bad. a simple plug change wont affect the throttle .

 

Not that I am aware of. Where is that sensor?

 

there is a little black box that is attached to the throttle body and has 3 wires that connect to it. try and unplug the wires and plug them back and see if this helps

 

will do. and thanks for your help!

 

i have right at 50000 on my 05 and from about 1300 till now at random(thankfully not to often) mine will do that. I have changed plugs(5224) and done other mods but every now and again it will do that exact same thing. It pisses me off so when it happens i rev the **** out of it and then it doesn't do it again for a while. I have read that alot of people have this problem, if you want to call it a problem.

 

I did what "super" suggested. I unplugged the wires at the throttle body and at the air sensor at the intake. plugged them back in and now it is running like a top! So, it is what it is. If it comes back, I will do the same thing.