So yesterday when I fired up my car it struggled to stay running I noticed my AFR gauge was reading pegged at 10.0 and it was mis firing no ses light though as the car warmed up the misfire cleared and my AFR got way better but it still bounces like crazy it will some times swing to 11 then to 16 and then settle at 14ish then start bouncing again...

mods on in the car are gsc s2 cams and all supporting mods with it
ets fmic upper lower pipes muse o2 dump full exhaust tuned in meth

Just to clarify this issue is new nothing changed on the car it’s on speed density so it not a leak and it’s much worse cold once warm the problem is a little better car is fin in WOT

 

What MAP sensor is in it?

 

When the car is first started it is in open loop. It takes anywhere from 30 seconds to five minutes for the engine computer to start using the oxygen sensor.

 

Has an Omni 4 bar in it I had a spare brand new one on the side so tossed that in to double check and I know till it warms up it’s in open loop but once it’s into closed loop and running off the o2 sensor it has large swings like from 12:1 to 16:9 on my AFR gauge while driving it cruises fine at 14:7ish but once in a while it will just swing to 11:7 multiple times in a row...

while watching my o2 in evoscan it will swing volts from .02 volts up to .9 volts I know .9 is correct but .02 seems low and it’s slow to respond

 

i had an 02 sensor go bad after doing a motor pull...
o2 sensors are funny... sometime just taking them out will make them fail.

anyway, instantly i noticed the car was idling at 11 afr... and even cruising down the road it was rich.
swapped the sensor... back to normal.

 

Ya my new sensor comes I tomorrow so hopefully it fixes it I’ve never had this problem since my tune from English racing if I boost it’s completely fine but then after that it can take a solid minute for it to come back out of the 11s AFR range then it just bounces all over the place

 

Yeah I have the same issues at times my tuner told me the o2 sensor is lazy, and that’s a sign it’s on the way out. You should be fine once you swap in a new one.

 

Just figured I would post guys got the new o2 sensor in and I let it idle for 10 minutes and drove it a couple miles and all seems good AFR are much more stable bouncing from14:4/15:0 which is a lot more stable no more super wide swing and it settles back almost instantly after WOT