Engine light flashes going up hills and loses power?

2004 PONTIAC GRAND PRIX
170,000 MILES • 3.8L • V6 • 2WD • AUTOMATIC
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KYBARRELRACER2000
  • MEMBER
  • 1 POST
I had the motors changed out with a 2006 GP a year and a half ago. All plugs and wires were replaced. The car wasn’t driven much until June of this year and now when it is put in a strain going up a hill it loses power, and the engine light starts flashing. The light goes back out when you level back off at the top of the hill. Anyone know which direction to take to fix this or diagnose it? Apparently, the reader can’t read if the light isn’t on.
Sep 15, 2023 at 1:53 PM
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JACOBANDNICKOLAS
  • ✓Experienced Mechanic
  • 110,248 POSTS
Hi,

If the check engine light is flashing, that indicates there is a misfire occurring at that time. So, that would explain the power loss.

As far as scanning, there should be a code related to a cylinder misfire. If the check engine light isn't on but the light was flashing, there should be a code or codes stored in history. Also, if you have a live data scan tool and connect it while driving, you should be able to see the misfiring cylinder.

Let me know. If we can determine which cylinder or cylinders are misfiring, then we can focus on possible issues.

Let me know.

Take care,

Joe
Sep 15, 2023 at 3:13 PM
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