P0131 Will not go away for the life of me...

Replaced BOTH o2 sensors, replaced temperature sensor, checked all wiring, Ohmed out the sensors, check continuity... P0131 still Pending.

P0299 Went away for about a week, Came back today... Replaced the TCV, Replaced hoses, No vacuum leaks, Waste gate functioning properly.

Someone please help me figure this out.

I am pulling my hair out.

*(COULD IT BE THE ECM IS BAD?!)*

 

The ECM hardly ever goes bad. It happens but it's rare.

How about a smoke test for the vacuum lines? (or unlit propane torch test) I'm just wondering if a vacuum leak could cause both the lean condition and the underboost. You said no vacuum leaks but the symptoms are otherwise. ??

 

I have checked and checked for vacuum leaks, I had a shop do a vacuum leak test and there are no leaks, I replaced the hoses I thought may not have been up to par, also... if I replace one thing, the OBDII will start throwing random different codes. Car was running 100% and all of the sudden the ECU is throwing Misfires on all 4 cylinders. got those to clear, then it started saying underboost issues, got that to clear, then it started showing no sensor of some sort (which is there and working just fine). Now either this is going to turn out to be an absolute lemon or this ECU and the spark plugs I am going to install today are going to make it work like a beauty. Any other idears? Thanks!

 

I'm cheering for you. I can't stand it when the car wins. Let us know how it turns out please.

 

Checked and checked and checked... replaced the ECU, no go... checked more and more... some little red and some little yellow color coded hose were swapped... Cleared EVERY code except P0131... waiting for mileage for it to clear. -.-