Ok so this problem has just started about two or three weeks ago and I have been trying to figure it out but can't!

It first started with a small misfire at idle, then got a bit worse, nest it started due it while cruising. I got new plugs and wires, I have played with the gap of the plus and it seems .030 works the "best"! :/

Now about a week and a half ago it started doing something else that just keeps me wondering.
When i'm cruising, giving it some, half throttle, or how ever else you can drive it will do this; when I let off the gas to shift or just let off for whatever, it goes ALL THE WAY Rich for a 2 seconds or so, then when I go to press the gas it leans all the way out and stays lean (17.0-17.5 or more) for a good few seconds (depending how fast I open the throttle. Some times it can stay lean for a while if i just have it on the slightest throttle position!

I have had a surging idle for the longest time I can't seem to fix and get worse in the cold (and i mean bad). And The misfire is still present!

But I was thinking the Throttle Stop Switch and Throttle Positioning Switch are bad! And thoughts on bad o2 sensor?
Also got a new diaphragm from my AFPR that im ging to put in (because i'm getting fuel leaking from seal *small leak*)
Would anyone agree with me on this, or can I get some advice?

Thanks,


Shawn

I have this EXACT issue..
Il be following this thread only thing is my car doesn't idle surge it falls on its face instead down to like 500rpm's sometimes but all the other symptoms i have are exactly the same..
Ive noticed sometimes it wont do it but usually it will and it is better when ive messed around near the throttle body..

First, check for exhuast leaks upstream of the wideband. Exhaust leaks can cause bizzare A/F readings.

The idles surge sounds like the ISC motor is bad, or ISC drivers on the ECU are fried.

Are you only using the translator to tune?

T is for TURBO said:

First, check for exhuast leaks upstream of the wideband. Exhaust leaks can cause bizzare A/F readings.

The idles surge sounds like the ISC motor is bad, or ISC drivers on the ECU are fried.

Are you only using the translator to tune?

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Tested the ISC, its good!
Send my ECU to ECMTuning, it was cleaned up but they reported back that it was Perfect!
I don't have any exhaust leaks that I can tell.
But its not just my wideband readings, I can actually feel it bog and hesitate when it leans out as I begin to press the throttle again for few seconds.

As for the surge, i'm on my last straw with that and planning on getting a new TB and blocking the ISC and the FIAV completely!
I was also thinking if my AFPR diaphragm was leaking maybe that would be causing messed up tuning situations and possible a funky idle! That i will be replacing here fairly fairly soon!

skatershawn said:

Tested the ISC, its good!
Send my ECU to ECMTuning, it was cleaned up but they reported back that it was Perfect!
I don't have any exhaust leaks that I can tell.
But its not just my wideband readings, I can actually feel it bog and hesitate when it leans out as I begin to press the throttle again for few seconds.

As for the surge, i'm on my last straw with that and planning on getting a new TB and blocking the ISC and the FIAV completely!
I was also thinking if my AFPR diaphragm was leaking maybe that would be causing messed up tuning situations and possible a funky idle! That i will be replacing here fairly fairly soon!

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Sounds like you have the basics covered.
Do have have ECMLink? A log would help us better diagnose the issue.
Also, do you know where your ISC position is?
A dead front O2 sensor could cause bad closed loop operation, as its purpose is to maintain proper operation during closed loop. But If you were to get on it, and get the car into open loop, your front O2 sensor would be ignored, so the problem would likely disappear and your wideband would show something much more normal.

If it is going lean while in open loop, you are likely getting knock, causing the car to pull timming, which migh explain the hesitation. Do you have the ability to check fuel pressure? The fuel pump could be on its last leg, and causeing the engine to not getting enough fuel. Also, check your timming to make sure you didn't jump timming.

No I don't have ECMlink, working on getting it from one of these awesome "Black Friday" sales.
I'm using the MAFT and I've only got 550's so it not too much to ask the MAFT to work for! :l
I have been meaning to replace the o2 sensor as I feel it may help, and its should be replaced anyway.
Yes I can check fuel pressure, got a gauge on my fuelab AFPR. (reads 38psi w/ line off, and at idle w/ line on its roughly around 28-30psi)
The pump is a Walbro 255 that is about a year old with around 10k miles on it. I would hope that isn't going out yet.

And I agree on the knocking from the lean issue!
If i start to accelerate at a good rate or do WOT(which i don't like to because of these issues) it runs as normal as it use to.

Thanks for the help and advice, its always easier for me to deal with these things when talking to people on here about it!

SORRY NOT TRYING TO THREAD JACK..Just figuered i have the same issue so il post hear insted of starting a new thrread and post my experiences aswell to try and get these cars fixed.

Well for my side of things i know its not the WB its brand new and i just changed the gasket from the downpipe to o2 housing and the front 02 sensor is less then 2months old..
Mine is either Pump related or electrical.. But i don't think pump as mine will do it sometimes then will go the entire day without doing it..

I tune with the safc2 and ive turned base timing down some hasn't made a difference(besides low end torque and power is down) and in open loop my car is fine..
I have retuned the car and it straight rips on 19 psi with AFR between10-11.4.. They are a bit up and downish but ive been getting them smoother before i try getting any more boost out of her.. Turning the base timing down robbed me of some low end power but the car is much smoother up top.. And plugs look great.

Mine only shows issues at low throttle and cruising/idling situations.. Like the weird misfire that will disappear for days then come back and the going lean at the initial jab of the throttle and feeling the car bog and then regain power as it gets back into proper AFR..

The lean issue is weird cause it will go to 15's and feel just fine and sometimes it will fall right off the WB readings and go completely lean..When it does that the car bogs bad then will richen up to where it would be normally and gain power and feel great..

I noticed it goes leaner and stays there longer if i give it less throttle like 15% or less.. If i give it like 15-20%or more it will go lean for just a second and go back to the 14's and pull fine.. And my TPS reads 100% when its all the way at the floor but if i check the voltage via safc2 the voltage is like 4.92 out of the 5 its supposed to be IDK if that little of a difference would cause these issues..

Ive also checked the ecu more then 3 times and that thing is mint looking..

skatershawn said:

I have been meaning to replace the o2 sensor as I feel it may help, and its should be replaced anyway.

And I agree on the knocking from the lean issue!
If i start to accelerate at a good rate or do WOT(which i don't like to because of these issues) it runs as normal as it use to.

Thanks for the help and advice, its always easier for me to deal with these things when talking to people on here about it!

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I replaced my o2 sensor in the process of trying to fix this and it didn't make any difference..You can try but i don't think thats your issue either man..

And i doubt your knocking at low rpm and throttle either as there isn't much load on the motor.. Just keep the AFR/egt's(no logger) safe if its under boost thats where damage is done.. And i totally feel ya about having people to talk to i get so mad when i have to deal with this car by myself but its so much easier if you know you have even 1 other person out there trying to help ..

skatershawn said:

No I don't have ECMlink, working on getting it from one of these awesome "Black Friday" sales.
I'm using the MAFT and I've only got 550's so it not too much to ask the MAFT to work for! :l
I have been meaning to replace the o2 sensor as I feel it may help, and its should be replaced anyway.
Yes I can check fuel pressure, got a gauge on my fuelab AFPR. (reads 38psi w/ line off, and at idle w/ line on its roughly around 28-30psi)
The pump is a Walbro 255 that is about a year old with around 10k miles on it. I would hope that isn't going out yet.

And I agree on the knocking from the lean issue!
If i start to accelerate at a good rate or do WOT(which i don't like to because of these issues) it runs as normal as it use to.

Thanks for the help and advice, its always easier for me to deal with these things when talking to people on here about it!

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Does your wideband read normal under this condition? By normal, I mean, not lean. If so, it would appear to me that your open loop operation is operating as it is supposed to, which leads me to believe your front O2 is dead/dying.

What are you using to log with? Are you able to see what your O2 voltage is while at idle/cruise?

Im going to tag in on this. I have a 2 page story of my car doing the exact same thing. http://www.dsmtuners.com/forums/newbie-forum/414032-gas-my-oil.html

Now what i have found is my TB is bad i had 3 boots leaks my up and down stream o2 was bad, i had a bad injector and my MAF was messed with so the calibration screw was wrong. Also on top of this my ICS, and my TPS were not getting a signal "bad", also my Temp sensor for the ECU was bad, and i had a hole in my intake manifold gasket and my injector seals were going out. So last thing i have to do is wait for my TB to get here Wednesday and replace it. Now i did convert my whole intake system and engine bay back to 100% OE.

My A/F is running "cruise" around 12.5-13.x and also 15 to 17 depending on what my car feels like doing. under WOT is about 10-11 and idle is pegged lean at ----- (past 18.2). Now i have taken my car to SEVERAL shops and have come up empty. I do have a repeated CEL that when i get it checked it comes up with no codes and no pending codes so they reset it and that same day if not the next it comes back and its a rinse and repeat. So encase someone comes up with something that i have yet to do PLEASE let me know.

Ive replaced every gasket between turbo and head twice.. Im thinking its a ICS or something to do with a sensor in that area as my car didn't show this issue one time yesterday and all i did was squeeze the plug that goes onto the ICS because it was loose and kept falling off..

Mine is WAY less noticeable now has been for about a month.. Have had this issue for about 7months so whatever it is it doesn't seem motor threatening..

And i don't think its a injector issue as my plugs all look almost identical and if it was and injector the issue would be there even when the cars in open loop mode.. My cars great in open loop mode and only shows the issues it has once in a while and ALWAYS in closed loop..

By any chance are you getting CEL?

775TSI said:

By any chance are you getting CEL?

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Nope..

Dammit why am i the only DSMer who keeps getting a ghost CEL.... Ridiculous i tell you. Well after my TB and ECU Temp sensor get here ill keep you informed on my status, also looking into a SAFC or V3 lite DSM link.

775TSI said:

Dammit why am i the only DSMer who keeps getting a ghost CEL.... Ridiculous i tell you. Well after my TB and ECU Temp sensor get here ill keep you informed on my status, also looking into a SAFC or V3 lite DSM link.

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Is the ecu chipped? If so it could be programmed to come up when the ecu sees knock.

I have no way of logging as of right now, i'm trying to get v3 lite to help.
my wideband reads normal while cruising minus the tiny hiccup misfire that just started a few weeks ago as stated previously. And again i stated when i let off the gas my wideband reads that the a/f goes completely rich, then when I go to press the throttle, it leans out and hesitates for a few seconds!
Other than that the wideband will be reading 14.6-15.2.

skatershawn said:

I have no way of logging as of right now, i'm trying to get v3 lite to help.
my wideband reads normal while cruising minus the tiny hiccup misfire that just started a few weeks ago as stated previously. And again i stated when i let off the gas my wideband reads that the a/f goes completely rich, then when I go to press the throttle, it leans out and hesitates for a few seconds!
Other than that the wideband will be reading 14.6-15.2.

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I also have no logger .. And ya my afr do the exact same thing.. They go to like 10 between shifts maby richer but thats as low as my aem reads... Other then that and the going lean at the jab of the throttle and the misfire my cars great ..

My misfire started out of nowhere a swell and i believe it to be something to do with the o2 sensor as i had the safc2 blue wire mod and the misfire almost has completely disappeared since i removed it.. It has just steadily disappeared more and more since i removed the blue wire mod.. I also have a small oil leak on the valve cover and it sometimes leaks onto the o2 sensor plug where the downstream part plugs in.. So that might be it aswell do you guys have any oil leaks in that area?

Shawn - If you "suddenly" started going lean during throttle tip-in for no apparent reason and nothing has been changed on the car, I would start looking for issues in the fuel system such as a clogged filter or a pump that isn't holding pressure. That leaking AFPR could also be the cause.

Going lean under driving conditions that require a quick change to fuel delivery (such as the ones you are describing) would point to this.

I have noticed these past two weeks ive been burning a tank a week driving 3miles to work and back and maybe a day or two out to get food when this type of traveling would only cost me a quarter of a tank or so.
Notice a slight amount of gas residue on and around my afpr, called Fuelab, and they sent me a nee diaphragm. Havent had time to replace yet, so dont have any update for that.
The fuel pump as around 10k ok it, guess it could still have issues.
Fuel filter was replaced when I rebuilt the motor, then again about 500 miles later and once more about 3k miles later (had OLD gas in the tank for a few yes. Couldn't empty so I added treatment and mix new gas in and changed filter)
I also dont have any type of CEL.

IDK if it makes a difference but i have also noticed a slight smell of gas too.. Under the hood and sometimes il just get a wif of gas inside the car.. Pretty weird. Maby i should tear into the AFPR and see if my diaphragm is ripped or something.

I'm not sure if the cause to my wideband readings is the AFPR diaphragm, but there are good signs showing that the diaphragm may be faulty, and if so, could possibly be causing some of the issues i'm seeing.
Just need to find time to take it off and replace it with out messing something up! (haha my luck i'd strip the bolts on the AFPR.)

Once I get that switched out, I will find out if that was the cause to the weird reading or not.
If fixed, I can continue moving on to finding the issue that is causing my misfire and idle surge.

Any updates?

Have you ran a BLT yet? I fixed my issues with a new MAS and ecu temp sensor. My car runs almost perfect now and i have zero issues. My car was doing this but in more a severe sense. Just because i bought and installed a new TB i went ahead and got a IAC /ICS. My CEL has been gone for 3 days, no miss fires and running around 14.5 at idle and cruise. I no longer smell gas and my car boost harder then ever.

No further updates other than the idle has gotten worse, and WOT in 3rd gear or higher it breaks up, stutters pretty bad! 1st & 2nd its just damn normal!
Also at idle my wideband would read flat out lean but smell like i was pouring gas around my car!!
All this happened right after I replaced my Injectors with some 550's off here! (except the looping idle but it wasn't as bad)
I'm starting to think the guy that sold me the injectors, sold me some duds!! :/
HATE buying used but can't afford new... and my 450's were shit.(reason i was looking for different ones)
I was looking at trying to find some 450s or something to replace these 550's and see if it helps any!

I replaced my Temp sensor last year sometime, and my mas is a GM MAF and have had small thoughts on it being a bit out of calibration.

Lol no updates..other then i found a exhaust leak where the mani bolts to the turbo and went to pull it and snapped the bolt.. Logged my car and im getting crazy PK so until i can get a new 2g knock sensor i let the guy i was borrowing the logger from have it back back.. Im going to save up and order a new knock sensor and some 850's or so and switch to e-85, get the logger back and tune it proper..

did antone ever figure out this problem, and solve it. I've had this since July. I've replaced almost everything under the hood.