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Discussion Starter · #1 ·
This is my daughters car so I have not experienced the issue yet myself. She says while driving the car it suddenly seems to loose power then seconds later regains power. She thinks it started after she ran out of gas a few months ago. I am looking for any input. It seems to happen mostly under acceleration. There is no obvious pattern with respect to the car being "cold" or "warm". Other than this the car runs great.
 

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She thinks it started after she ran out of gas a few months ago.
Have you tried to scan for trouble codes?

One thing that comes to mind is when she ran out of gas.
The low pressure gas pump in the tank doesn't like running without fuel to cool it.
Possibly an intermittent fuel pump problem.
 

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Discussion Starter · #3 ·
No I have not scanned for codes other than her saying that the engine light has not come on. I do have a cheap reader so I'll try and look for any stored codes when I can but she is at college. Hopefully it keeps running until then.
 

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Discussion Starter · #4 ·
Finally was able to check for codes and no codes are stored. I checked the fuel pressure with a gauge and it is 60 psi with key on and then drops to about 50 while running and then bouncing around a little as the RPMs change which seems about normal to me. Apparently this is the pressure from the pump in the tank which feeds the high pressure pump. Looking at the real time data on my scanner I see something called FRP which runs around 375 KPa. If I convert this to PSI I get roughly what I saw on the gauge so this as well looks to be the pressure from the tank pump into the high pressure pump. Does anyone know if the high pressure side of the fuel rail should show in my scanner and if so what is it called ?
 

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Discussion Starter · #5 ·
I found both high and low fuel pressures in my OBD2 scanners real time data and compared it to my other Equinox. Low pressure hovers around 300-400 KPa while high pressure goes as high as 10,000 KPa and down to about 4,000 KPa. It seems to be the same in both cars but I could smell gas in the oil so I replaced the high pressure pump and changed the oil. My daughter reports that the problem still exists although I drove the car and did not notice any issues. I am thinking some how the transmission might just be shifting slightly different than prior. Either the transmission has developed some slight issue only she detects given she drives it every day or something else is having a slight issue and confusing the computer. Given it is very easy I may switch MAF sensors next given I noticed differences in the real time numbers for MAF. It is had to diagnose something I can not feel myself.
 

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I found both high and low fuel pressures in my OBD2 scanners real time data and compared it to my other Equinox. Low pressure hovers around 300-400 KPa while high pressure goes as high as 10,000 KPa and down to about 4,000 KPa. It seems to be the same in both cars but I could smell gas in the oil so I replaced the high pressure pump and changed the oil. My daughter reports that the problem still exists although I drove the car and did not notice any issues. I am thinking some how the transmission might just be shifting slightly different than prior. Either the transmission has developed some slight issue only she detects given she drives it every day or something else is having a slight issue and confusing the computer. Given it is very easy I may switch MAF sensors next given I noticed differences in the real time numbers for MAF. It is had to diagnose something I can not feel myself.
Did you ever figure out what the problem was? My 2014 gmc terrain is potentially having the same issue it sounds like...
 
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