Bouncing afr while cruising

[Chaycem]

I’m having an issue with my Actual AFR bouncing from 13.7ish to 15.7ish very rapidly back an fourth while cruising around 30mph and only around that speed. Once the car has driven a few miles the problem stops. This happens every day on my regular drive. Other than that I keep normal afrs and feel no real hesitation. I can’t seem to think of anything so any insight is appreciated.

Im currently running stage 1 91 Cobb ots and have been for over a year without this problem.

I have 0 other performance/mechanical mods other than a GFB dv vta

again anything will help because I’m stumped. And I can get data logs if anyone is willing to look

 

[Clint Beastwood]

I’m having an issue with my Actual AFR bouncing from 13.7ish to 15.7ish very rapidly back an fourth while cruising around 30mph and only around that speed. Once the car has driven a few miles the problem stops. This happens every day on my regular drive. Other than that I keep normal afrs and feel no real hesitation. I can’t seem to think of anything so any insight is appreciated.

Im currently running stage 1 91 Cobb ots and have been for over a year without this problem.

I have 0 other performance/mechanical mods other than a GFB dv vta

again anything will help because I’m stumped. And I can get data logs if anyone is willing to look

Did you just recently start monitoring it, or have you been monitoring for a long time and it just started doing that? I ask because your O2 might just not be up to temp yet. I don't know about the FiST o2 sensor, but others I've had needed time to get some heat in them.

 

[Chaycem]

Afr has been the one thing I have consistently monitored since I bought the AP. I thought the same thing because we had record lows in my area like -1 ish. but it has warmed up recently to about 40 to the mid 30s and still the same issue.

 

[TyphoonFiST]

Go back to stock tune* monitor and see if it happens with stock settings. This will determine if it's the Cobb tune or not. Then I would proceed to get and e30 tune Via Jason @ Dizzy tuning or Alex @ stratified.

Sent from my SM-N975U1 using Tapatalk

 

[Chaycem]

Go back to stock tune* monitor and see if it happens with stock settings. This will determine if it's the Cobb tune or not. Then I would proceed to get and e30 tune Via Jason @ Dizzy tuning or Alex @ stratified.

Sent from my SM-N975U1 using Tapatalk

I already have flashed a Stock tune on and it still persists.

 

[Chaycem]

So I’m lost at this point, I have so far

Replaced my air filter with a high flow
Replaced my upstream 02
Replaced my spark plugs
Deleted the symposer
Replaced my gfb dv+ vta with a turbo smart compact shortie dual port
Done crc turbo safe valve and intake cleaner
Gone to the stock map for a while now
Switched gas stations three times, cenex connoco and chevron my regular
Checked all of my charged air connections

all of that and the problem still persists if anyone has an idea please let me know

 

[Intuit]

Assuming this is abnormal behavior, check for unmetered air. Read all four spark plugs to insure consistent appearances. Compression check each cylinder.

 

[FiestaSTdude]

Did you ever figure out what was wrong?