My ka24de has had a rough idle for awhile now. I’ve done the timing, changed plugs, wires, cap, rotor. Cleaned the AIV. Adjusted the idle. Still it has a rough idle. It sits at 800rpm but every 10-20 seconds it hiccups and drops about 50-100rpm and sometimes up to 300 or so rpm(that doesn’t happen often). I am at my wits end, I’m replacing the maf with a unit that rob gave me. I ran my ecu codes and it came up with 55(which means, no code). I need help. I’ve been thinking its the aac valve on the iacv. Does anyone have any ideas? Please help Please help Please help
Check all the vacuum lines?
Which ones would I start on? Which ones would be the most likely cause? Could it be the small vacuum line coming off of the intake tubing before the throttle body? Where does that tiny one lead to? It’s a little bent and may not be open enough to be clear.
Don’t have a KA so not too sure. I just know both times my idle went wonky was because of vacuum lines. Check them all, see if any are loose/not connected.
I had that problem when I first bought the car, it was an exhaust leak. right at the manifold, the piece was replaced and the rough idle stopped!!
THEN just recently I had another idle problem, but it was due to a headgasket. Since that has been replaced no more idle problems, actually idles fast. Even loosening the idle screw just barely settled it down enough.
Could be your fuel filter is old?
Oh, I forgot to say, I just replaced the o2 sensor as well as the fuel filter at the start of spring.
Engine coolant temp sensor.
If you can see a 2 prong temp sensor try to wiggle the wires and if it changes the idle at all
i also had a rough idle on my ka single cam. it turned out it was a vacuum line stuck open .works kinda like a piston. its circular and has 2 lines comining from it one from the side and one from the bottom. its next to or underneigh the throttle body. get 2 fingers in underneigh it and pump it a couple times.
I had a really rough idle not too long ago. Changed the plugs, things were fine. Now it’s back, just less rough. I’m confused.
:edit: Yeah no, it’s back. In full swing. I’m worried my engine is dieing.