Need help. Car throwing DTC code P0191

[Loudness]

So my car has been bogging pretty hard lately its an 05 GT MMR 2.8 Kenne Bell. During my drive on the weekend the check engine light came on and this is what the SCT found.... Code description is P0191 - Fuel Rail Pressure A. Anyone know if this is what has been causing the bogging? Has anyone had this issue before?

Thanks in advance!

BTW I'm new on this forum!

 

[jayman33]

MMR is your problem /thread.

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[TexasBlownV8]

Check your FRPS. And your fuel pressure as measured by the pcm.

 

[86GT351]

Probably the Fuel Pressure rail Sensor!

 

[Big50]

Hey Guys,

I'm the previous owner of the car and I'm trying to trouble shoot this with loudness. Let me provide a little more background.

Yes It's an MMR motor but it was built approximately 2 years after all the large issues with this site. It was assembled with TPS Motorsports though and I've had nearly 10K trouble free miles with it. If it were an issue with MMR it would have more then likely been within the first 1000-2000miles.

The bog developed a day after I sold the car. We had it smogged here in CA and it passed the sniffer with flying colors. The code appeared about a week or so after the bog developed. I had never had an issue with it and it seems to be horrible timing as it developed just after I sold it. To trouble shoot so far we have:
-changed the fuel filter
-changed plugs
-changed sensor that threw the code

We are having a tough time diagnosing the issue at this point. We don't think the motors damaged as it pulls hard as ever in full throttle. Just bogs in lower rpms and sometimes on shifts.

A few things I think it may be are:
-o2 sensors going bad. I've reloaded the tune and it seems to go away for 30-60 seconds and then comes back. Although, odd that they would go bad a day after smog. But loudness did have several street races which could have been the final straw to break the camels back.
-stock cats are going bad
-boost-a-pump is going bad or something is wrong with it. It's a GT500 fuel pump plus KB BAP.



Any input from you guys who have had issues like this in the past would be most appreciated as we are stumped right now.

 

[Black3vGT]

I've thrown this code handful of times over the past year, it bogs a few times then trips the check engine light. When I clear the code it goes away every time immediately. I am assuming it's just a bad fuel rail pressure sensor, although it happens mostly when i'm low on gas(like under 35miles)

 

[JeremyH]

If you replaced the frps and you still get that code. Then its something else in the system bleeding off pressure. The code is thrown due to the pcm not being able to maintain delta pressure. My issue was fuel leak from one of the pumps in the tank. This was causing the pcm to keep increasing voltage to the pump to try and compensate and eventualy messed up one of my pumps. Replaced the hose and pump and all is good.

I would check all the fuel system wiring, make sure the bap has a good ground etc, the hat itself in the tank and the injectors.

 

[Alfiedagr8]

Jeremy is correct. P0191 means low fuel pressure. Diagnose y u have low fuel pressure.


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[Big50]

^^^Thanks guys. I appreciate the input!

 

[86GT351]

What type of tuning? Do you use SCT?