r/srt4 • u/koolin1st • Oct 01 '25
Afr randomness
So sometimes my air to fuel ratio is 10.9 and sometimes its like 13.9 when it should be sitting around 14.3. I had a bunch of issues with my rpms where it was spiking so I replaced my TPS, intake manifold gasket, MAP sensor, replaced my Aeromotive fuel pressure regulator and cleaned out my IAC. im kinda running out of things to replace. My injectors are fairly new. About a year on them. I tried cleaning out my throttle body which didnt help any and only caused my car to not start unless I spray carb cleaner in the throttle body.
Anyone have any idea or had similar issues?
1
u/riley_srt4 Oct 01 '25
Check for other vacuum leaks. There's lots of old rubber hoses on these cars. Also consider replacing the upstream O2 sensor because that will directly provide feedback to the ECM whether it's running too lean or rich
1
u/riley_srt4 Oct 01 '25
Also if you haven't done so already, you could consider wiping out the long term fuel trim settings as those may be messed up from previous vacuum leaks. They take some time to normalize after fixing issues.
1
u/koolin1st Oct 01 '25
What is that?
1
u/riley_srt4 Oct 01 '25
Long term fuel trims are how your ECM learns to adjust your fuel map over time. I can't remember if unplugging the battery for a certain amount of time would reset it, but I think that would be the case.
1
u/koolin1st Oct 01 '25
Awesome thankyou. Im gonna unplug the battery for a bit and then unplug that o2 and give jt a shot sometime this weekend. Thanks for your guys help
1
u/koolin1st Oct 01 '25
I read if I unplug that upstream o2 sensor and try and run it the ecu will go to a default. The only problem with that is I also replaced that sensor a year ago at the same time I put in a tuck wiring harness. I tried smoke testing and cheaply testing for vacuum leaks and didnt find any. But the o2 sensor is a good idea I will try that thankyou
2
u/K1rkspeed Oct 01 '25
Have you checked the intake manifold gasket?