My tranny has been slipping when at WOT. So I though that maybe I was on the last leg of my tranny when the stumble developed and that it just wasn't shifting. Then I started looking at my Scanmaster readings and seen that my RIGHT O2 sensor was only reading 003-011 millivolts and my LEFT side Integrator was shooting up over 200 when the stumble occurs. The car runs fine in first gear even though the readings are like I stated. Then when it goes from the 1-2 shift it starts to stumble and surge and continues up to 60 MPH. After it gets to 60 MPH the readings look normal again and the car runs fine. What could be causing this? It doesn't seem like it could be my tranny. Also, this is happening under normal load. The car is a 95 A4. Any info. is helpful.

Thanks.

 

Anyone?


Sorry, I don't mean to put this ahead of everyone else's, but it's my daily driver. I can't afford to go without if any longer than I have to.

 

Does it just sound like a bad O2 sensor? I need to get this thing fixed a.s.a.p. So ANY ideas are VERY appreciated. Thanks.

 

If you have your old MAF you could swap it out just to make sure that isnt the problem

I dont know anything about o2s ,

 

Your O2 sensor voltage should always be changing going from 900 to 100 etc. during normal driving.

If you have around 100K miles you should swap out the O2 sensors.

But it could also be bad injectors on that side. You could check by swapping sides like put the driver's side injectors on the passenger side and vice versa.

How bad is the stumble?

 

The stumble is pretty bad. It flutters real bad and sounds like it's flooding out. So I guess it's more than a stumble, because it's not something that just happens real quick. Like I said it starts right after the 1-2 shift under normal acceleration and continues up to 60 mph. After it gets to 60 mph, it does it for a second then smooths out and runs fine. The Scanmaster also shows that the O2 starts working properly at this time. I'm leaning toward the O2 being bad since, I only notice the problem after the car goes into closed loop. I just wanted to make sure that I wasn't dealing with something that was more serious. Thanks for the help so far guys.

Oh and one more question. Why would the Right O2 be giving a faulty reading of 003-011, but the Left Integrator reading over 200 at this time? Thanks again.

 

BTW Gripenfelter. I just changed the O2's (put Bosch's in) last fall when I installed my headers.

 

Ok. Now I'm stumped and pissed. I just changed the passenger side O2 and the same $hit is happening. The car runs fine when in open loop. Then when it goes to closed loop the popping, fluttering, and surging occours. I'm lost. If you have ANY ideas please feel free to share them.

 

Disconnect your MAF and drive in open loop.

See if the problem occurs.

If it doesn't occur, then its a sensor problem and probably nothing serious.

You just have to find the sensor by trial and error.

 

So what will it do when it goes into closed loop with the MAF unplugged? What should I be looking for?

 

Just unhooked the MAF sensor and took a little drive. I did a couple of WOT runs and a couple of normal driving runs. The problem never happend. Both of the O2's were reading under 100 millivolts the majority of the time. But with the MAF disconnected the problem never occured. Any ideas on what sensor could be bad? Thanks for the help so far Gripenfelter. I owe ya already.

BTW, is it ok to drive my car with the MAF unplugged until I find the problem. Or should I let it sit?

 

Could it be the MAF itself?

 

I hope not. I just sold my stocker.

 

Can you borrow one from a buddy to test?

 

Well if I can use a MAF from a 98 TA, then yes I will borrow my buddies. Will a 98 work on my 95? I doubt it that'd be too easy.