Lean idle/cruising with misfire at idle only

[92nolatist]

Ok here it goes, searched and nothing came up for my certain situation.

Whenever i drive around town just cruising with my foot barely on the gas, my AEM wb02 reads from 17.0-18.0 and even goes to the three dash lines (---) and the same thing when it idles fully warmed up. It also misfires/sputters pretty bad, but only at idle and fully warm. In boost (WOT and half throttle) A/Fs are perfect.

Now, my question is how can i fix this? I dont think I have any boost leaks but my boost gauge always sits at 15 in hg at idle. New TB gaskets and o rings, New IM gasket and injector seals.

I was thinking it could be my TPS is bad or possibly a fuel filter?????? Plugs are only a few months old.

If somebody could please help me out, I'd greatly appreciate it because its getting to the point of me not wanting to drive the talon ### i dont want any failures.

Thank you.
Dave Moore

 

[jeffo]

What are your fueltrims doing?

 

[92nolatist]

Not a clue, datalogger not working. But it did start happening right after i put in a dsmchip.

 

[rts91tsi]

Sounds to me like you need to add some fuel at idle and low trim.

 

[92nolatist]

I tried on the translator but it makes the car want to stall. The idle knob is fully leaned and that is the only way it will run decent.

 

[rts91tsi]

Have you tried using a larger injector setting on the translator.

 

[viprez586]

Check for exhaust leaks. Do this by running seafoam through a vacuum line in small increments while your buddy revs it to 3k.

Not only will you clean out carbon, but you'll find where your exhaust leak is, if you have any.

A leak anywhere before the O2 sensor, and your wbo2 - will throw the reading off.


Edit* A healthy motor should pull 18-20inhg of vacuum. 15in is low unless you have cams. Keep checking for leaks, or do a compression test and/or cylinder leak down test.

 

[92nolatist]

It makes it worse. Set on 430cc right now (lowest setting). DSM chips said zero out all knobs and it was horrible so i had to set them all back up to what they used to be before the chip.

Edit: Viprez586- did this a couple times before and there was one in my manifold which i have sinced replaced with a FP race mani.

 

[rts91tsi]

If it's set to 430cc, I would at least set it to the stock injector size on the translator. I take it your chip is setup to control your injectors.

 

[92nolatist]

Correct on the compensation. I could try setting it to stock, Im gonna go try that and ill get back to you.

UPDATE: It didnt do jack shit. Also, i forgot to ,mention that i am getting horrible gas mileage which doesnt make any sense. If i am running lean wouldnt that mean i would get better gas mileage??