Low power and sticking transmission?

Tiny
RYDER1477
  • MEMBER
  • 2004 CHEVROLET IMPALA
  • 3.8L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 188,000 MILES
My car listed above LS 3.8L is super low on power. When going uphill, the transmission doesn't kick down to grab a lower gear (it does once in a while) it has hardly any passing power on level ground, and just the other day after barely making it up a clear dry road, it was stuck on high RPMs. I don't know what to make of it. This came just one week after I had zero warning lights for the first time since I owned this car. Any thoughts of what to check?
Sunday, March 2nd, 2025 AT 2:30 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 50,193 POSTS
It sounds like you have a weak fuel pump, jumped timing chain or a clogged air filter. We should run the codes though even though the check engine light is not on.

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

If there are no codes let's check the compression on the engine and check the fuel pressure.

https://www.2carpros.com/articles/how-to-test-engine-compression

and

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

Fuel Pressure (Key ON Engine OFF) .................... 364-405 kPa (53-59 psi)

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Monday, March 3rd, 2025 AT 11:02 AM

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