gradles21

Ok guys I've never posted in a forum before so forgive me if I sound like a noob. I've searched every forum I could find about this issue and I still haven't been able to fix this issue. I drive a 99 LX D16y7. So my idle issues started a few months ago at a stop light, I had the car for a year up to this point with absolutely no issues. So I was at a light and all the sudden the rpm started surging from 800 to 2000 until I turned off the engine and restarted it. It would do this only a few times a week but never gave me a CEL. I read that this issue was most likely a iacv so I ordered a new one and installed it, the surging stopped but would idle high, usually around 1200 rpm. At almost every stop now the CEL will show up and give me a P0505 code and immediately start running like s*** until I could reset the code and then it would run fine but still idle at around 1200, or I can hold the rpm at about 1500 and the CEL won't come on but that's getting annoying. I also did a idle relearn procedure after I installed the iacv. I figured I just got a bad iacv so I was able to return it and I ordered another but ended up having the same issues. So with all of the forums I've searched and youtube videos I've watched including ericthecarguy this is what I've tried: bled coolant system, replaced iacv twice, cleaned TB, replaced plugs and wires, checked for and fixed the vacuum leaks that I found with carb cleaner, bled coolant system again, turned idle speed screw all the way down. After all of this I'm now stuck, please help someone I'm sick of having the pull over on the side of the road to reset the CEL

Brandon@fattysmotorsports

Tried replacing throttle position sensor?

gradles21

I unplugged the tps with the engine running and the idle immediately changed and the CEL came on so I'm assuming the tps works

Brandon@fattysmotorsports

Well then the tps works fine. I hope you don't have to get a new ECU.