Still stumped

[asite57]

Ok so I had this LTFTS problems they were 16.4 at idle....not good checked for vac leaks and couldn't find any in the big places, the idle has always been a little rough, I just kind of ignored that then I changed my tstat and not the fuel trims are anywhere from 3.4-14.5 at idle it varied at every light I stopped that was in D while in P it's 16.4 all the time. I'm kinda stumped any thoughts are welcomed

info on the car: 1999 GTP mods are in sig all fluids, wires, plugs have been changed it has 181K on the clock

[asite57]

Also my vacuum at idle is 19psi and my boost at WOT peaks at 5.9psi (in 70* degree weather)

[Slappyn]

I suggest pulling the plugs to look at them as the color and condition can tell you a lot. While you have them out do a compression check. You can pick up a gauge for around 30 bucks and some places or people may let you borrow it. Get the Chilton or Haynes book or just look online to see what the gauge should do and what it will do if something is wrong. Don't forget the wet check of the cylinders with a little oil. After that you can try a vacuum test. I had a vacuum gauge for camper brake system in my cab on my pu and one day the gauge fluctuated on start-up. Two weeks later I was changing the head. Check for codes as well and if you can spare it look at the application "torque" for android and get the blue tooth adapter for 30 bucks from e-bay or amazon and start looking at engine info until you find something out of limits. Best to work it now than in the snow miles from home.

[asite57]

Alright I have the torque app, I don't burn oil or lose any at all so compression is fine, I told you my vacuum -19psi at idle

[91parkave]

your LTFT's are a sum of your STFT where were they at at idle? FYI tourqe is good but dont totally base your numbers off it, in order to nail that issue you might need to talk to your tuner again. and have him/her run through all of your VE/MAF tables etc...

[asite57]

I mean I don't solely go off it but I do have a buddy with a bone stock 2000 GTP and his LTFTs are solid -3.4% at idle (don't hold me to that number it's been awhile since I checked his I know for a fact it was solid though not bouncing around like mine)

[asite57]

Btw my plugs are fine changed them 3K ago with stock replacements

[91parkave]

Keyword bone stock your tuned and BTW was it a local tuner or ???

[asite57]

Local tuner problem persisted before the tune

[91parkave]

well hardware wise if youre not leaking anywhere and your MAF and all other sensors are in working condiotion there should be no issue besides your tuner.....i would try to reflash a stock file and start over making sure you knock the VE and MAF tables out first. BTW i have tourqe and HPT thats why im telling you not to rely soley on tourqe as half the time its inaccurate for things like fuel trims.

[BillBoost37]

Since you are still stumped. Why not keep this all in one thread instead of people having to guess at what has been suggested etc?

[asite57]

Sorry bill the last thread was old and I've talked a lot in chat about it
And yes all sensors are working fine, gonna look at the tune again soon

just so I know the only harm of messed up LTFTs are bad MPGs and less power right?

[BillBoost37]

Depends on how "messed up" they are

[asite57]

The numbers are above^^^ what's your thoughts?

[91parkave]

your number would indicate youre running very lean so whatever you dont go WOT until you resolve this issue

[asite57]

I don't really floor it this is not a race car lol

[asite57]

I wish I could log data with torque

[Slappyn]

I have pro and it does some data logging but I don't know if it is what you need.

[Slappyn]

Alright I have the torque app, I don't burn oil or lose any at all so compression is fine, I told you my vacuum -19psi at idle

You might be right or you might be wrong. Oil loss does not equal poor compression even though it could. They are a simple place to start. Does the vacuum fluctuate? Like I said, my gauge started fluctuating two weeks before I had to do major maintenance. I have a dial gauge.

[mskram1]

i had the same problem for a long time as many of us do... its a vac leak and theyre tricky bastards because they could be anywhere... i ended up getting a new sc gasket and using some grey rtv around the blower outlet and lim inlet and that seems to help but didnt completely fix the problem... im leaning more towards severely warped lim in my case because ive got 258k miles and other contributing factors aka former pizza kar