I am about 8 months into this repair. Some of you may even remember my posts from last summer.
It all started when I lost both fuel pumps. Replaced them and the FPR/Filter. In addition replaced cam sensors, which lead to the famous "Tee" piece vacuum line hack on back on the engine.and intake manifold gasket replacements. Plus a few broken plastic vacuum lines.
After it was all done just couldn't get past Bank 1 and Bank 2 lean codes, no misses, so I took it to the dealer and they determined it was an intake manifold leak (Self inflicted - I must of let the gasket slip out somewhere during the DIY and it was leaking). After paying highway robbery to get it repaired by the dealer I did not even make it home when the exact same codes came back, plus a ton of mis-fires! So I dropped it back at the dealer the next day and about a week later they give the the diagnostics and repair estimate. $1800 for valve cover gaskets, coils and plugs. They insisted that was the culprit and I challenged them, I took the car home to DIY, that was a fun job.
I put in valve cover Gaskets, brand new proper plugs and Beru coils and guess what? Bad idle, stumbling, etc. and every cylinder misfiring with all the same codes lean codes.
Anyone have any ideas now? I have a few:
1) Maybe FPR is bad or one of the fuel pumps isn't up to spec and its actually fuel starvation causing lean codes and misfires?
2) There is still a vacuum leak even after they ran a smoke test and fixed it.. (Going to try and run another smoke test this week)
3) Every one of my new Beru coils from pelican is bad...

Appreciate any wild *** ideas. This is been months and cubic $'s and it still isn't right.
Thank you

 

The dealer is now tasked with FINDING your vacuum leaks.... not just proposing to gang-rape the tourist. Have them "honor" their warranty!

 

That's quite a list of codes.

I'd start with what was changed just prior to these issues: fuel pumps/filter/FPR.

What does your fuel pressure look like over time? Is it low or dropping out? Clogged filter? Bad FPR?

What do your ST and LT fuel trims look like? Is this an intermittent issue, or chronic? Low, med, or high RPM issue? Have you done some logs with the Torque app or Durametric?

It's possible you have a massive vacuum leak, but the proximity of these issues to the fuel system repairs is more suspect.

Also, just to rule out the MAFs, have you tried unplugging them and seeing how it drives (and what codes you get)?

Also, what repair caused the dealer to want to replace your exhaust gaskets? That's not common around here - - Lupo and J'sWorld aside, few have touched the exhaust manifold.

 

Thanks Brainz. See *** below

That's quite a list of codes.
I'd start with what was changed just prior to these issues: fuel pumps/filter/FPR.
*** Agreed, that could be a "Common denominator"
What does your fuel pressure look like over time? Is it low or dropping out? Clogged filter? Bad FPR?
*** Have not looked at that yet. I replaced both fuel pumps, FPR, and filter. Did I mess up the tubing? Don't know, maybe? or it's not unheard of for New Parts to be bad. One of the fuel pumps is not bad, same either at 1/8 tank or at 7/8 tank fuel.
What do your ST and LT fuel trims look like? Is this an intermittent issue, or chronic? Low, med, or high RPM issue? Have you done some logs with the Torque app or Durametric?
**** Don't know.
It's possible you have a massive vacuum leak, but the proximity of these issues to the fuel system repairs is more suspect.
**** Agreed. Going to smoke test it. Not expecting that is an issue.
Also, just to rule out the MAFs, have you tried unplugging them and seeing how it drives (and what codes you get)?
**** Yes, actually runs worse when unplugged.
Also, what repair caused the dealer to want to replace your exhaust gaskets? That's not common around here - - Lupo and J'sWorld aside, few have touched the exhaust manifold.
**** Duh, typo in my part. Meant to type Intake Manifold Gasket. THAT caused a leak. Sorry, good catch.

 

Got it. Do a fuel pressure test, log fuel trims and check for vacuum leaks.