02 3.4l inconsistent idle

Picked up a super clean 02 double cab 4x4 last week and have been doing some maintenance. The only real problem I've been having is an inconsistent idle. It would idle anywhere from 500-1000rpm and kind of jump around. The pre purchase inspection said it needed new plugs, so i replaced those with OEM plugs yesterday and while I was at it, took off the throttle body and cleaned it really well and got the IAC valve as best I could too.

It seems to have significantly helped the idle. It now at least tries to stay at 750rpm and will sometimes idle perfectly, but it will still randomly rev up to 1000 a few times back and forth. Under any sort of load the engine runs like it's new.

I didn't replace wires, but the wires on there looked fine, no corrosion or anything. I plan on changing the fuel filter and the PCV as well as the serpentine belts later this week. Any other ideas on what I could do?

 

worn and old...throttle position sensor

get a new OEM one (only oem), disconnect battery, reconnect bet problem goes away

 

Check the EVAP line connected to the airbox right around the MAF. Mine was torn and affected the VSV and the idle. Replaced the line and now it idles like new.

 

Ordered an OEM one, hopefully that'll fix it.

Just checked and that line looks perfect. Can't find any deteriorating lines.

 

Duuuude. Got my TPS in yesterday but wanted to try and pass emissions before I put it on since I knew I'd have to reset the ECU. Passed emissions this morning, drove home, pulled the EFI fuse, replaced the sensor, and then started the truck up. Idled almost perfectly at 1k. I let it do that for 5+ min and came back and it was idling at 600rpm steady. Went for a drive and it's perfect now. Thanks!