I ran a search on this but couldnt find what I was looking for. Closest thing was this: https://honda-tech.com/zerothread?id=768633 . I have the same problem as he does when my engine warms up, the pulsating. I also have a CEL but it doesnt give a code when I go get it checked out. I have a 98 Civic EX. Using the EX Wiring Harness, Boomslang OBD-2B to OBD-2A jumper harness, P2T(99 Si) ECU. I had to extend a few wires to make the EX harness fit (but i knew that had to be done). One sensor is missing. IAC sensor is the one i think (on the back of the intake manifold), but the sensor is the same shape as the sensor that is on the vaccum line to the charcoal canister. switched them out and my rpms when starting the car sat at around 2000 and it still pulsated.. im f'n confused.. help please

 

please help

 

need help!!!

 

just swapped my in this morning and having the exact same problem, if u have found out anything please let me know

 

Check the ground connection on the thermostat housing and make sure its snug.