Running weak?

Tiny
PONTIACPEOPLEPERSON
  • MEMBER
  • 1995 PONTIAC GRAND PRIX
  • 3.1L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 95,000 MILES
I have the car listed above SE model. It seems to be running weak, barely gets to 3,000 RPMs when flooring it. It still gets up to speed just I feel like with a V6 I should be thrown back in my seat, lol.

Any ideas? Brought it to the shop for a "tune up" and they cleaned the fuel system and installed TR55IX and 4641 tune up parts.

Seems to run a little better after that but still not enough power. It doesn't stall or anything. Has a little jerk in the idle maybe but very slight. Starts up fine and no check engine lights on.

Would love any ideas or suggestions.

Thanks!
Monday, January 18th, 2021 AT 2:51 PM

7 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,723 POSTS
Has anyone checked for a plugged catalytic converter? A potential clue is the sound at the tail pipe will be a steady hiss instead of the normal pulsing sound. Your mechanic should have a back-pressure gauge to test for this. It involves drilling a small hole in the exhaust pipe ahead of the converter, then you stick the gauge's probe in there to measure pressure while the engine is running.
Was this
answer
helpful?
Yes
No
+1
Monday, January 18th, 2021 AT 4:14 PM
Tiny
PONTIACPEOPLEPERSON
  • MEMBER
  • 5 POSTS
Thank you! I'm not sure but I will look into it. Is this something I should get checked out immediately or am I good to drive it around for now?
Was this
answer
helpful?
Yes
No
Monday, January 18th, 2021 AT 4:42 PM
Tiny
PONTIACPEOPLEPERSON
  • MEMBER
  • 5 POSTS
I can't hear any hissing, just "glug glug glug etc."
Was this
answer
helpful?
Yes
No
Monday, January 18th, 2021 AT 5:07 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,723 POSTS
A plugged converter can lead to engine overheating. Another way to check for it is to unscrew the oxygen sensor. Leave it connected to reduce the chance of setting a diagnostic fault code. Also don't unplug it while the ignition switch is in the "run" position. Setting a fault code while working on the system can confuse mechanics in the near future when there's codes set that aren't really indicating a defect or problem.

You might also look at these articles:

https://www.2carpros.com/articles/engine-has-low-power-output

https://www.2carpros.com/articles/symptoms-of-low-engine-power

Low power can also be caused by a timing chain that has jumped one tooth. This starts to be a good suspect at the mileage you listed.

Whether it's okay to drive it depends on what is wrong and if it will get worse. Take a look at this article too:

https://www.2carpros.com/articles/bad-catalytic-converter-symptoms
Was this
answer
helpful?
Yes
No
+1
Monday, January 18th, 2021 AT 5:44 PM
Tiny
PONTIACPEOPLEPERSON
  • MEMBER
  • 5 POSTS
So I figured it out. My floor mat was stuck up under the gas pedal : |

Much anticlimax.

Thank you anyways.
Was this
answer
helpful?
Yes
No
Wednesday, January 20th, 2021 AT 7:33 PM
Tiny
PONTIACPEOPLEPERSON
  • MEMBER
  • 5 POSTS
Oh, one other thing. The mechanic said I could get some kind of aftermarket sensor to help the car MVAP or MAP or I can't even remember. Any ideas what he was talking about?
Was this
answer
helpful?
Yes
No
Wednesday, January 20th, 2021 AT 7:34 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,723 POSTS
Not sure what he's referring to.

Happy to hear you solved the problem. That would take a while to figure out when you can't see it. Please come back to see us with your next problem.
Was this
answer
helpful?
Yes
No
+1
Wednesday, January 20th, 2021 AT 9:08 PM

Please login or register to post a reply.

Sponsored links