Car dipping low RPM/stalling when depressing the clutch

[loserbro]

Hey guys, I've found some threads similar to my issue but mine's slightly different and I can't really find any ideas so I figured I'd ask you all:

The other day, I pulled my clock fuse to get my EPS to reset (had the EPS light on and no power steering). It's back to normal in that regard, however I've introduced a new problem. While driving, when I depress the clutch and pop it into neutral while slowing, the RPM drops SUPER low, like maybe 300 or less RPM, causing the car to shake a little bit, and occasionally full-stalls. The thing is - it KINDA did this before pulling the clock fuse, but it would drop to like 600ish then stabilize at 700-800, but now it dips to or below the cutoff line and then stabilizes back at 600ish. While sitting still and idling, it's not hunting or anything, stays stable. After pulling the clock fuse, I let it sit and idle for about 10-15 minutes like I always do, then shut it off and went to bed. Anyone have any ideas what might be going on? Normally, my first thought would be throttlebody or IACV cleaning, but the fact that it got exasperated so badly by resetting electronics makes me think that it's something else.

Thanks for your time!

 

[Old Guy]

You didn't specify the year of your car; but, your comment about the IACV (actually EACV in the NSX service manual) suggests that it is pre drive by wire so your car is moderately old.

When you pulled your clock fuse, you erased your long term fuel trim values. Normally, this should not create a problem unless the car is running with a lot of fuel trim at idle. If the ECU is running with a lot of fuel trim, that is an indication of some other potential issue. If you drive around long enough and let the car idle long enough once up to operating temperature (the engine needs to be up to operating temperature otherwise the ECU does not go into closed loop operation), you will eventually re establish the fuel trims. At that point you should have an idle that is back where it was before you pulled the fuse. Then you can work on figuring out why that idle is less than satisfactory (Cleaning the EACV and checking the base idle setting as described in the service manual would be a good place to start).

 

[Larry Bastanza]

First thing to do is clean the idle passage on the throttle body. I see this all the time.

HTH,
LarryB