08 GT Starts and then immediately dies

RR5150

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Jul 14, 2019
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Last weekend my 08 GT started with a bad idle and then died on us while we were 250 miles away. I was able to get it started again and we made it home
but since then it will intermittently start and run ok and idle just fine until I rev it up and bit and then it will sputter and die at idle.
After that it will only fire up but not continue running, giving it gas does nothing. Lately though it only fires up and dies right away.

What I've tried:
1) Cleaned the throttle body
2) Replaced the MAS after cleaning it didn't help.
3) Replaced the fuel filter, I can hear it engage, could hear the old one too.
4) Replaced the fuel pump
5) Replaced the Throttle body motor
6) Replaced the fuel rail pressure sensor due to a CEL, CEL went out after.
7) Replaced the TPS

The CP's were replaced with Accel's about a year ago, plugs were done then too. I used a can of starting fluid to check for vacuum issues, haven't found any yet.
I can't get the car to run long enough to check for an arc.. :-/

I've run out of ideas, there are no codes.


Help?
 
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RR5150

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Jul 14, 2019
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I can definitely hear it engage as did the old one before I changed it out. I'll look for 12V tomorrow.
It fires up like it wants to run strong as new but then dies.
 

fiftyslost

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Jan 1, 2019
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Had similar problem. The fuel shut off switch on drivers side kick panel kept tripping. I bypassed the switch and have not had a problem since. Just a thought.
 
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RR5150

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Jul 14, 2019
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Had similar problem. The fuel shut off switch on drivers side kick panel kept tripping. I bypassed the switch and have not had a problem since. Just a thought.
That's soemthing I will have to check out for sure, thanks!
 

RR5150

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Jul 14, 2019
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Had similar problem. The fuel shut off switch on drivers side kick panel kept tripping. I bypassed the switch and have not had a problem since. Just a thought.
I bypassed that switch today, had no change.
This morning I started the car up and it idle up and down a little bit at first and then smoothed out. I was able to rev the engine and let it return to idle. I shut it off and abd tried to start it again and I'm back where I was. It fired up strong like it wants to run and then immediately dies.
 

RR5150

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Today I learned that if I I spray brake cleaner into the intake it'll stay running just as long Iong as I keep spraying it in.
 

Shuttleman83

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Jun 30, 2019
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Check valve maybe restricted or faulty, try priming the fuel pump roughly 3 times in succession. Key on, off, key on, off, key on, then start. Some fuel pumps actually need this.
 
Sep 3, 2018
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Johns Creek, GA
I had a similar issue that incredibly was solved by my neighbor - fuel pump just wouldn't supply fuel sporadically. Swapped the fuel pump relay with an identical relay and BAM SOLVED. The contacts just weren't making contact. WEIRD HUH. Been 6 months and 0 issues since. Car was sitting and would crank/not start, swapped relays, started immediately. Hit all the contacts with contact cleaner for good measure after that ridiculous experience.
 
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RR5150

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Jul 14, 2019
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Check valve maybe restricted or faulty, try priming the fuel pump roughly 3 times in succession. Key on, off, key on, off, key on, then start. Some fuel pumps actually need this.
I tried this, no change. I also swapped a relay as Troublesome suggested.

This morning after letting it sit for a couple of days I went out and tried to start it and it fired right up, bit of a rough idle at first but it smoothed out. I then let it run for five or six minutes while I went around and started wiggling wires, etc to see if I could make it stall. I couldn't.
Eventually with me doing nothing at all is stalled out on its own. Now it just starts and dies again.

I didn't do the sending unit underneath the passenger side of the tank, I only did the complete assembly under the drivers side, could this be the issue??

THIS MAY BE FIXED:

A few days ago I got a P0193 code thrown. Fuel rail pressure sensor. I went to AutoZone and got a new one, put in on and the code went out.
Today out depsperation I put the old one back on and it FIRED RIGHT UP. I let it idle for a while and shut iff and started it again. So next I took it down the road, no issues. Could be that AutoZone sold me the wrong/bad part?? Looks like it $500 in parts later.
 
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RR5150

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The fuel rail sensor, not the fuel rail. The part they sold me had to have failed but never tripped a code. It still running like a top.