im having an issue =( at cruising and driving around town, which is stop and go, i usually run anywhere between 12.5-13.0, and at full boost. (7psi) im at 10.1-11.4, Now today i turn on my car to warm up for 10 min. then im off, and i notice light accelaration my AFR's were at 16-17.8 i was like wow!! thats not good. then under boost it falls down to 11.2-12.4. then i jump on the freeway and at cruising 70mph my AFR's are at 16.8-17.9 but mainly in the 17's. can you guys let me know whats happening? im running 550's with stock fuel rail and fpr. with a walbro. its a built LS/Vtec motor with standard timing.

it freak me out because arriving to work it was in the 17's and it started stuttering in the parking lot before parking.

 

anyone>? =/

 

look for exhaust leaks before your wideband sensor
check your alternator

 

calibrate your wideband in free air. good safe tune should be around 11.5-12.5 afr in boost, 14.5- 15.5 afr cruising under mild load.

 

just checked and there is a exhaust leak on the weld of my downpipe.
alternator is fine.
i have the wide band bunged on my dp

how do i calibrate it in free air? its an AEM wideband, brand new.
i got it tuned at DNR the past weekend. it was fine untill today.

 

and it did feel sluggish and starved.

 

I had the same problem it was the iat and ect correction table

 

The exhaust leak will cause your a/f ratios to be off...you should fix that...

 

how did you resolve it?

 

what tuning software
this should only be done by some one who knows what there doing
First check for exhaust leaks

 

My AEM wideband does this at time too. When I does I notice my volt meter dropping down. Once back up to 14 volt it's fine again.

 

true, but he said the car started studdering which leads me to believe it really was running that lean rather than just a incorrect number on the gauge.


unless the wideband is sent to the ecu to run a open loop...


as said, check your voltage. also just a crapshoot but if you have a gm 3 bar map sensor check that. ive had 2 go bad on me in the past few years and this was what was happening to me

 

I recently ran into that same issue.

While driving on the highway its at 14.7-15.5 normaly @ 14volts.

Randomly my volts are dropping down to 12.0-12.4, changing my AFR's to 17.5-18.3 range. When this happens I also have a miss at idle or hesitant while driving.

Might be a loose connection or a failing alternator.

 

tuner tuned it on Crome on 7lbs, untill i get stand alone. there is an exaust leak on the dp weld.

thats exactly what i said. it started stuttering. its wierd. im saving alot of fuel on highway though! ha. but not funny.

i do have a GM 3 bar. i might just have to buy a volt meter to have in my car and keep an eye on. how do you know if the 3 bar is bad?

Thats exactly what is happening to me JDMs1eeper. hmm im going to check my connections. alternator seems fine, but i'll check it.

 

How old is your O2 sensor ?