My car has been running like complete **** lately. It idles like a big block with a huge cam most of the time going from 800 rpm to 1500 rpm then back down to like 500 almost stalling out. Other times it runs fine. It's also been sluggish lately and a few times getting off the highway under deceleration the car has just died and the motor stopped running, all while doing 60 mph+ on an exit ramp. Last night I finally got a coupe DTCs which were P2097 and P2187. Which are both fuel trim codes. Any ideas what can cause these? I have a K&N SRI and I've had it for ~1 year and never had a problem before, also catless DP on a stock tune. Also when I hit the brakes harder than normal the car almost stalls out, lights dim, RPMs drop very low and it has never done that before this issue.

 

Sounds intake related. My car idles funny with my intake and stock tune file. Could also be your HPFP going bad.

 

Are there any codes?

 

P2097 and P2187

 

Sounds to me like you might have a big vaccuum or boost leak.

 

If you don't have an intake that your aren't tuned for, then you need to run a boost leak test. See my sig.

Edit: I see OP edited in more info. If the intake hasn't been a problem previously, go for the boost leak test first.

 

That's what I am afraid of, but the car hits full boost and considering the brakes affect it, it could be vacuum. I've checked and haven't found anything.

 

Maybe evap issues. Try unpugging your evap purge solenoid. Or boost leak.

 

Having an intake with no tune does not make ur car act like that, iv had both Hahn and k&n on stock tune and car ran totally normal with it

 

This. Evap Purge Solenoid for the win, Alex.

 

Also I should mention that with those 2 codes on my fuel trims were going crazy skewing all over the place, with STFT going all the way up to ~30 under acceleration. LTFT is anywhere between 7 and 14. Also I clear the DTCs and they never came back but the car still runs horrible albeit the fuel trims are a little better.

 

Ya I tried that before I posted. It seemed to be better at first then it just started throwing evap system codes. I was just trying to see if anyone else experienced this problem. Probably time to search for a leak. Thanks

 

It will throw codes if you unplug it, the car thinks it's not longer there or broken. Question is, does it run right better?

 

Sox fan could it be coked Inlet valves is causing all this? OP is your car under warranty still?

 

Certainly could John. You know that more than I ever will. My argument to that though, is that I was under the impression that coking is a more gradual process and this seems to have come on fairly recently and rapidly.

The good news is that it's really easy to test. Some blow through it or what not, but I say unplug it, if the car smooths out and then stumbles again when you plug it back in you've got fair evidence that the solenoid is bad.

That's not to say that coking is not present.

 

yup the reason coking "suddenly causes issues" is that it is indeed a gradual build up, but the point at which the build up causes issues is a 'one day it happens" thing. Did i say that right.

Kinda like an 02 sensor gradually deteriorates until one day it sets a CEL. etc.

 

Fuel trims appear to be less skewed but the car still runs rough. Seems extremely sluggish even though making full boost. Also like I said car shuts off under heavy deceleration and almost stalls out under hard braking.

 

Yes I still have a powertrain, bumper to bumper is gone. I was trying to avoid taking it to the dealer because I don't want to have to go back to stock because from my experience they are much stricter on the powertrain warranty.

 

I recently had a nearly identical problem. STFT ~30 and AFR would drop down to like... 9 even just cruising and the car would nearly die.

In my case it was the primary O2 and I cleaned the MAF.
It runs fine now. Mine only threw the primary O2 code once, otherwise it threw other crap, like secondary O2 and misfires.

Of course it might be something else for you but that was my experience with a very similar issue.