1999 Tacoma 5vzfe up and down idle

Making this because I have run into an issue, my truck while driving runs perfect and smooth, but during idle it’ll go up and low enough it feels like it’s about to stall but just doesn’t. It doesn’t show the up and down idle on my rpm gauge, it’ll shake a little bit during that moment and if I put it in gear and move at snails pace it’ll do 2 things; do little jerks forward or it’ll do what it’s supposed to and roll forward, my thinking is it’s my IAC valve or sensor, and I know I don’t have any vacuum leaks (nearly drove myself mad doing so)

 

Might be worth taking a look at your throttle body - I know dealers love selling throttle body cleaning, but after 21 years there was a lot of black crud built up partly blocking the throttle plate where it was supposed to sit at idle.

 

Look at your fuel trims when she is behaving badly, same for your MAF readings. Press the brake pedal a few times too, boosters are a "hidden" vacuum leak.

 

i ended up getting my codes ran at autozone yesterday and it’s saying the intake air temp sensor is on its way out or is already out


It happens when in park too

 

Part of the MAF... for fuel injection parts use only toyota parts, expensive, yes, but there are lots of stories on the forum where an aftermarket part was used and they spent the next 2 months chasing problems due to incompatability.

 

the injectors i bought for it;https://www.partsgeek.com/yjhrqql-toyota-tacoma-fuel-injector-kit.html

I haven’t changed the MAF yet since it’s still working

 

Update: I replaced my upstream o2 sensor and that fixed the issue