I’m working on an 02 Accord V6. I just did a valve adjustment and when it warms up I get a surging idle between 1000-1200 RPM. I double checked all the hoses and sensors. No error codes unless I yank the TPS or MAP sensor while it’s running.

I also replaced the spark plugs and coils.

I sprayed all around the throttle body, hoses, and intake with carb cleaner with no change in RPMs. I replaced the manifold gasket and torqued to spec. Replaced the IAC and made sure coolant was full and getting both hoses hot on the IAC. Replaced the MAP and ensured it was all cleaned out. TPS is holding .499-.501v closed and moves smoothly. I can stick my fingers in the IAC port and it idles down correctly.

After it heats up and surges for a minute, the surges becomes quicker with less variance but still surging.

I’m out of ideas. Smoke test the vac system?

Also if I clear the codes it starts surging again.