Another 240sx with idle issues.

[Whitehatchwonders13]

I know this has been gone over plenty of times but I was just hoping to see if I can get some guidance on my idle issues.
So about two weeks ago my ka24de started acting up, sounded like it was running on 3 cylinders, muffler sputtering, so I figured I'd give it a tune up. That was about 8 days ago, now its not doing that anymore. Recently though, its developed an idling problem, if I have the ac on it idles fine since its at a higher rpm, but if I have it off and I'm at operating temperature the idle fluctuates between 800-1100 rpm and its annoying cause the car shakes and I can hear my chain slapping the guide at lower rpms. I've cleaned the maf twice before and tried adjusting the idle but the screw is already all the way counter clockwise, my car also has a walbro fuel pump and is running a bit rich because of it. Could it also be the iacv or the tps sensor?

[jza80king]

Have you tried pulling any codes? I would say try cleaning the IACV and go from there.

[Whitehatchwonders13]

Surprisingly the check engine light is not on, but I'll go ahead and start with that and see if that fixes anything.

[SoundEfx]

Have you tried new coolant sensors?
It help a little with my rich idle.

[Whitehatchwonders13]

I should try that too. Do you think its possible that I might have altered the timing when installing a new distributor rotor?

[Cone Killer]

I had the same issue on my 91 KaDe, I didn't have a CEL but when I pulled the codes I had a bad knock sensor. Replacing the knock sensor helped, but it would still idle rough. Then one day it started running really bad, felt like a fouled spark plug, but all the plugs and wires were fine. So I would pull one plug wire at a time until I found the "dead cylinder". Turned out to be a bad injector, after replacing it the car idled better but was still rough, so I changed the rest of the injectors and that fixed it. It idles so smooth now, you can't feel it running.

[Cone Killer]

Do you think its possible that I might have altered the timing when installing a new distributor rotor?

No, unless you loosened the distributor mount and you turned it, but just replacing the rotor won't change the timing.

[Whitehatchwonders13]

Well, cleaning the IACV seems to have smoothed out the idle, but now since its idling at a normal level I can hear my chain slapping against the guides. Another project awaits!!!

[SoundEfx]

It never ends because if it did, you'll get bored with the car.

[jza80king]

Well, cleaning the IACV seems to have smoothed out the idle, but now since its idling at a normal level I can hear my chain slapping against the guides. Another project awaits!!!

it's never ending man, until you die. If I could tell you every time i've told myself 'this is the last thing I need to do' and then I buy more s***. I own a Supra so that is my other money pit lol