rough idle if reversing too soon after startup

[kolosy]

found this odd behavior lately where if i start the car and put it into reverse right away, it almost stalls out. rpms drop to below 500 and it starts trying to save it, jumping all over the place. if i put it back in neutral for a few seconds it stops, and then reverses fine. same thing if i wait a few seconds before putting it into reverse.

haven't tried the same thing with a forward hear since i'm usually backing out of a parking spot, but will.

any suggestions? the fuel breather valve is newer (2018 date code)

[omgzirra_exe]

Originally Posted by kolosy

found this odd behavior lately where if i start the car and put it into reverse right away, it almost stalls out. rpms drop to below 500 and it starts trying to save it, jumping all over the place. if i put it back in neutral for a few seconds it stops, and then reverses fine. same thing if i wait a few seconds before putting it into reverse.

haven't tried the same thing with a forward hear since i'm usually backing out of a parking spot, but will.

any suggestions? the fuel breather valve is newer (2018 date code)

Hmm, I experienced this issue at cold start. What I was experiencing was that upon a cold start, the car's idle was erratic for a second. Additionally, when I put the car into gear (first or D to drive off), the RPM drops abruptly but then recovers.

At that time, I had a SAP error code that lingered. I ended up blocking it off, and I never had the same idle/RPM drop-off. My diagnostic skills were poor at that time, but I just never had that issue again. The SAP will cause the O2 sensors to read incorrectly, so I chalked it up to that. Bank 1 SAP was the pump that failed for me and was clogged.

in your case, it could be alternator? maybe car isn't getting enough voltage. For all i know it could be alternator for me also LOL.

my car idles just above 550rpm as well normally. for a reference point.

[kolosy]

Originally Posted by omgzirra_exe

Hmm, I experienced this issue at cold start. What I was experiencing was that upon a cold start, the car's idle was erratic for a second. Additionally, when I put the car into gear (first or D to drive off), the RPM drops abruptly but then recovers.

At that time, I had a SAP error code that lingered. I ended up blocking it off, and I never had the same idle/RPM drop-off. My diagnostic skills were poor at that time, but I just never had that issue again. The SAP will cause the O2 sensors to read incorrectly, so I chalked it up to that. Bank 1 SAP was the pump that failed for me and was clogged.

in your case, it could be alternator? maybe car isn't getting enough voltage. For all i know it could be alternator for me also LOL.

my car idles just above 550rpm as well normally. for a reference point.

you know it's interesting that you say that, because i have a bank 1 o2 fault that won't go away (installed new o2 sensors), and an occasional SAP fault. wonder if it's all the same thing.

is coding it out enough, or do you physically have to block off the SAP?

[omgzirra_exe]

Originally Posted by kolosy

you know it's interesting that you say that, because i have a bank 1 o2 fault that won't go away (installed new o2 sensors), and an occasional SAP fault. wonder if it's all the same thing.

is coding it out enough, or do you physically have to block off the SAP?

you can tune it out but not code it out. and you can leave the hardware there.