TypeXFan

Ive done a fair share of searching and work on my car and still no fix.

I own a 91 240sx Hatch, ka24de motor. After the motor is warmed up the idle starts fluctuating bad....it gets to the point where it eventually dies out. There are even times where if I drop the clutch the rpm sinks down to where it almost stalls out(couple of times it has stalled).

The most logical thing was to take out the iacv and clean it out. Didnt fix the problem. So I decided to go all out and do a complete intake manifold overhaul. I took out the manifold and cleaned it up, replaced the iavc again, cleaned the throttle body, replaced all gaskets, and did a complete vacuum line swap with high grade silicone lines, and added a ground kit.

I now have no vacuum leaks (yes all the lines are in the correct places), I have a clean iacv and intake manifold with all new gaskets, and the problem is still there.

The check engine light has come on and the code its throwing is 55.....as far as I know code 55 means all circuits are good. I dont know what else to do, its pretty depressing to do all this work and dump all this money and not fix the problem. The only other thing I can think of is replacing the o2 sensor.

I could use some advice from you guys.....thanks