I went out to start my 2006 Chrysler Pacifica (48000 miles)on a very rainy day and it didn’t want to run. I tried pumping accelerator as it tried to die and I won out. I drove it several miles and then went in store for an hour came out and had a replay of not wanting to start and getting it going. Drove home and parked for a day. It starts fine but at 3000 RPM it runs up and down or what I would call a pulsing action. No check engine light. Any ideas ?
Possible vacuum leak, a faulty IAC (Idle Air Control) valve and/or a dirty throttle body.
Another one could be a loose or broken TPS (throttle Position Sensor).