While at idle the afrs go from 14 to 18 on my wideband which creates a hesitation and a rough idle then the o2s must pick this up and returns to 14.2 and the idle clears up.Also every now and then the car once its warm hesitates and splutters for a short moment while cruising at low speeds and wants to buck when in first gear.Wot its perfect.With my obd11 there indicates no missfire,and the o2 sensors seem fine,anyone possibly no whether this is tune related. Its driving me crazy

Thanks

 

WOT & normal driving are basically different tunes. Idle fueling could be a number of things. Sounds like the MAF table scaling is off. Did you change the MAF without changing its' scaling? When's the last time you cleaned the little MAF sensor resistor wires?

The once warm issue could be the ECT tables, but more likely also MAF related.

 

Currently dealing with the same during initial warm-up from a cold state. It seems to be a OL to CL functionality issue. My O2 sensors are slowly switching or not at all; I am running Bosch units and looking to go to Denso or NTK replacements shortly.

It could also be a ground issue causing both O2 sensors to react slowly; as I do find it odd that they would both crap out at the same time.

 

Im not running a maf.

 

Everytime I've had a lean idle situation was a vac leak. Mine would peg at 17 a/f, and my leak was after the TB.

 

Ive currently unbolted the cat pipes as im thinking its leaking between the header pipes and where the cats bolt up.This could be causing the leak before the 02s.Ive checked all hoses in the engine bay and cannot find any cracks or holes.TB is very clean as well as tps.Its only started since i finished my m6 conversion.If anyone else has any ideas to where any possible leaks could be that would be a help.

 

Would have been good info to note in your post. Did you confirm whether or not unbolting the cat pipes has caused the leak? Also, you can eliminate the 02 issue all together by running OL.

 

Are you saying keep it in OL forever? Cause that would be a little rough on MPG right?

 

Why? I run OL MAF & can get 30+MPG highway by leaning out normal driving fueling. You have a wide band & can use it to set up the OL fueling table.

 

Ok after finally checking for vacume leaks and everything else a million times,when at cold start idle it idles mint until it gets to 70 degs once it get to that it goes lean to 18afrs then after a bit the o2s bring it back to around 14 afr and idle clears up.So this morning it was doing the same thing then i jacked the car up disconnected the o2s and now it idles perfectly and sits on 13.3-13.5 afr on the wideband.Maybe they have been turned off in the tune or are my 02s shagged?

cheers
Glenn

 

Did you ever fix the problem. I have the same issue!