in the video then u see the a/f gauge start to go wacky jumping around u can feel the car jerking back and forth. like @ 33 seconds

YouTube - A/f %

 

when its spiking u can hear the kind of whistle noise a little

 

mine does that occasionally too. i think its b/c of the catless dp b/c after i installed it thats when that **** started happening. a/f would be all stupid like that and then my cel would pop on with an o2 sensor code. i had vince delete the code but i still notice once in a while that my a/f will do that for a few seconds and then level off. like the car is trying to throw a code but cant bc it was deleted.

 

hah thats nothing man. Mine use to spike up to 18 then go to 12 then level off while i was just cruising on the interstate

 

Wow that thing is really freaking out.

 

Purge Solenoid or the Front O2. The Purge is $18 shipped when I bought it and the O2 is $65ish. I have a spare Purge if you want me to mail it to you to try out?? PM me your addy

 

In nuetural every car goes to 18 I'm talking about foot on the gas

 

No, in neutral you should not be getting 18:1a/f. In neutral or with the clutch pushed in, even while moving, you should be stoich (around 14.7). The only time the car will hit a crazy lean number like 18:1 and leaner is during a decel while still in gear (dfco). Generally during dfco you should be seeing around 20:1 and leaner..

Either way, your a/f's are definitely doing a nice little dance there. Are you hitting any boost at all when thsi happens? Even like 1 or 2 psi?

 

Ive found most cars will do this if you BARELY press the throttle.

 

They all do this if you are right on the edge of being in DFCO (really light throttle). My car does it sometimes and it did it bone stock as well.

 

ok Interesting that you say that you hear a "whistle" while spiking.

Mine does the SAME thing. I have narrowed it down to it being the fuel pump believe it or not maybe that sounds crazy . It is the weirdest sounding thing.

My opinion is the fuel pump is just dieing or it isn't right. with the high pitch squeal under spiking .. Most people who are full cat back probably can't even hear it, you still have the stock exhaust besides the dp right

 

nope not boosting at all..

 

still on the stock exaust w/ catless dp... some ppl have said it sounds like a spooling jet... lmao