2009 Enclave seems a vacuum leaks issue.

[GAEV23D49J]

Hi All!
I'm new here and first of all, I'd like to send the best wishes to this nice community.

I've inherited the Enclave 2009 that hasn't any move since 2017 year. I've changed the battery and try to start. The engine has run, no strange noises, the transmission also works fine. But when I'm trotting above 1500-2000 rpm the engine has stopped suddenly. No check engine light. I've had no fault codes via the OBD scanner.
So, I've checked most of the important data via OBD and found that the vacuum value is too low. For example, on idle it is near -100 and after throttling it is rising to zero and even above zero!
All oxygen sensors are OK. The entire intake tract is clean. No oil inside the MAF sensor and the throttle is also clean.

Please help me sort out with this problem.

Thanks in advance.

 

[MelsRegal]

Did you drain the old gasoline ?

 

[GAEV23D49J]

No. Why need it? I have doubts about the case when water in the fuel. But I'll try it tomorrow just in case.

 

[GAEV23D49J]

I've checked it. The same result.

 

[MelsRegal]

You checked what?
Do you still have 3 year old gasoline in the vehicle?

 

[GAEV23D49J]

You checked what?
Do you still have 3 year old gasoline in the vehicle?

I've drained old gasoline and fill a couple of gallons of fresh. Nothing changed. The vacuum problem still exists.

 

[MelsRegal]

Would expect a severe vacuum leak to throw a O2 sensor code.
The term you are using, vacuum value and the reading of -100, can you explain that?
Vacuum readings are typically measured in inches and could range from a low of 8 to a high in the 20's.
Have you done a fuel pressure test?

 

[GAEV23D49J]

Would expect a severe vacuum leak to throw a O2 sensor code.
The term you are using, vacuum value and the reading of -100, can you explain that?
Vacuum readings are typically measured in inches and could range from a low of 8 to a high in the 20's.
Have you done a fuel pressure test?

I've attached screenshots from the OBDII scanner. Also, I've made the same screenshots from other Buick that working fine (Lacrosse 2008). And I made a mistake, excuse me. It's pressure in the Evap emission system, I'm sorry for my mistake...
I

 

[GAEV23D49J]

Test results are attached also.