99 Galant idle problem

[denniscariot]

I've searched all over the place and haven't been able to find this exactly, so hoping someone else ran into this. My idle started surging, up and down, up and down. I replaced the IAC with a used one and for two days the car idled perfectly. Now it idles low on startup and once warm will not hold idle. I can two foot it and keep it going that way but any time I let the RPM go below ~800 the engine just stops. In the interest of clarity, it literally stops running the moment it drops below 800, no sputtering, rough idle, or any other symptoms. Any ideas?

[saulv]

check tps and clean maf sensor

[denniscariot]

Hey, thanks for responding. I was just going to repost today. Here's the deal: I reset the ECU and the idle straightens out for about eighty miles or so, then starts to misbehave until at around 100 miles, it won't hold idle at all. I haven't had time to look into this due to other projects (gotta keep old landlady happy) but are your suggestions consistent with this behavior?