Rough idle when warmed up

[whodini]

Hello everyone! This is my first post here I've been following the forum for quite a while though. Definitely my fav forum! I've found all the info for all my maintenance and troubleshooting through the search feature. This time though I'm stumped.

I've got a 2000 3.4 and everything was fine. Absolutely love the truck. I am running into a problem after the truck has warmed up. It starts to idle rough, drives fine but as I slow down, park, stop, or reverse it idles rough. Like it's surging. I've swapped out the plugs, wires, maf, air filter. It ran fine after the plugs and wire swap (oem). 2 weeks later it's back at it again. Not sure if this has anything to do with it but i swapped the head unit out for an aftermarket one a couple days before it started happening again. I just put in some injector cleaner a couple days ago to see if it clears things up but it doesn't seem to be doing anything. We'll see in a couple more days.

Any suggestions or comments? My engine light has come on again so I'm going to get it scanned again but am pretty sure I'm going to get the same misfire codes. I don't think it's the coil packs cause I get the misfire on one cylinder. Seems to be a common problem. Anybody ever get this fixed?

 

[whodini]

Will not hold idle at 1800

Just also wanted to mention that if I try to hold the idle at 1500 -1800 it will hold for about 8 seconds then it will just drop to about 500 rpm then slowly climb back up to whatever rpm I'm trying to hold it at?! Any ideas?

 

[whodini]

Rough idle problem

Well to make a long story short... was going to get my codes read but my friends wife just delivered last night a beautiful healthy girl at 6:45 sooo I guess I could wait on getting my codes read.

Ended up popping the hood to poke around just to make sure everything was hunky dory and lo and behold the fpr line was off :ybrick:. Hooked back up and confirmed everything is fine now. Mustve either popped off which i doubt or i just forgot to put it back on after changing the plugs and wires. Strange thing is why it would take so long for the problem to pop up? That's why i'm thinking it popped off. Anyway for those of you who may have come across something like this after changing out your plugs make sure all those darn hoses are hooked back up :lmao:!