Grand Prix loses power every 60 seconds, help!

[The Mad Hatter]

Hello all! Long time lurker, first time poster. I've been scanning all the forums looking for someone who's had this issue but i've yet to find anyone, so i'm asking for help. My 2007 base Grand Prix has developed and issue with the power to car "blipping" for just a split second, but it's enough to cut the engine off while driving. It will start right back up immediately, but here's the weird part, it does this blip about every 60 seconds now. Here is what i have attempted so far to fix:

-Replaced the crank position sensor with a brand new one

-Replaced suspect battery terminal that i'd had trouble with before

-Switched ignition relay with horn relay (known working relay)

-Jiggled ground cables (this did not cause a blip)

None of these fix attempts rectified the issue. I have no codes stored, and no dash lights (other than the tire pressue sensor, hate those things). I'm stumped so i'm out here looking for help. I'm not great with electrical so any help is greatly appreciated but bear with me as i figure it out. Thank you in advance for any help, this is my daily driver and it's stuck in my driveway, i can't trust it. I will try to add a video of it blipping when i get home tonight but I don't know how much that will help, all i can hear is some relays clicking and the fuel pump priming. It does this with the key on ACC or running, but obviously if it does it while running the engine shuts off. It does not do it with the key off. Thanks again for any help!

 

[FordMan77]

Ugh, I HATE electrical issues. Check the wiring harness that goes to the underhood fusebox. Sometimes they can corrode where the wires enter at the bottom and cause strange issues. Another thought is to check all your grounds. Just because they are tight doesn't mean they are clean.

Judging by your description of relays clicking and the fuel pump priming it does indeed sound like all power is being lost and the key cycle starts over again. I may suspect the ignition switch at this point since you say it does it in ACC or while running. Just my .02

 

[GXP02]

Ugh, I HATE electrical issues. Check the wiring harness that goes to the underhood fusebox. Sometimes they can corrode where the wires enter at the bottom and cause strange issues. Another thought is to check all your grounds. Just because they are tight doesn't mean they are clean.

Judging by your description of relays clicking and the fuel pump priming it does indeed sound like all power is being lost and the key cycle starts over again. I may suspect the ignition switch at this point since you say it does it in ACC or while running. Just my .02

^^^^^^^^^^^What he said^^^^^^^^^^^. I would inspect the underhood wiring harness for broken wires/shorts. Especially around the throttle body area.

 

[GXP02]

Also look in the air cleaner box. Mice love to chew on the wires by the ecu. Pop off the beauty engine cover and look for mice damage there also.

 

[onxy]

Just out of curiosity, when you say there's no codes stored, do you mean in JUST the PCM? (Engine computer) Or the whole car? There's a chance that one of the other modules has a code stored that would point you in the right direction.

 

[The Mad Hatter]

Just out of curiosity, when you say there's no codes stored, do you mean in JUST the PCM? (Engine computer) Or the whole car? There's a chance that one of the other modules has a code stored that would point you in the right direction.

The engine computer. I have no check engine light before or after the cut out. Scanner shows no codes before or after the event, it actually loses connection to the OBD when the blip happens and has to reconnect. I'll clean up the grounds, but the time repetition makes me think some electrical component is shorted and overheating at ~60 sec intervals.

 

[The Mad Hatter]

After replacing the ignition switch, the problem still exists but it is now randomly occuring instead of every 60 seconds.