1994 Pontiac Grand Am Vibration and noise, as well as loss

Tiny
KHAAN
  • MEMBER
  • 1994 PONTIAC GRAND AM
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 225,000 MILES
Hello, my 94 Grand Am seems to be running a little weird now that winter is here. When it is cold, or if I haven't ran the car in awhile, the car doesn't seem to respond as well when I push the accelerator. It almost feels and sounds like a fuel issue, like its not combusting properly or something. It's hard to explain, but when I press the accelerator, it is noisier than usual, until it warms up, and it also feels sluggish, I would say, until it warms up. Any ideas? Also, since the day I bought the car, there is a slight whirring, and vibration whenever I get to a higher rate of speed. It is especially noticeable on the highway, and the noise and vibration is not constant, but it is in a pattern. It vibrates and makes noise for like a second, and then stops for a second and then does it and then stops. I was wondering if this could be the harmonic balancer. I read somewhere about torsional vibration or something like that. I would really appreciate any suggestions you could offer. Thanks!
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Tuesday, December 9th, 2008 AT 6:22 PM

5 Replies

Tiny
BUDDYCRAIGG
  • EXPERT
Sluggish.
Maybe air intake sensor, or engine temp sensor.

Vibrating noise.
Does it sound/feel like it's coming from the engine/tanny or the suspension of the car?
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Tuesday, December 9th, 2008 AT 11:17 PM
Tiny
KHAAN
  • MEMBER
The engine temperature sensor is on or near the thermostat housing correct? And is there a way to check either of those sensors? Also, I was wondering if it could be anything to do with my fuel injectors? I'm not sure whether or not the temperature can affect how well they work, or if the car being warmed up makes them work better. I am doubting that, but I have been considering replacing them anyways so I figured I would ask.

As for the noise, I forgot to mention something that to me seems like a major clue. When I go over a bump in the road, the noise changes with the bump until my suspension absorbs the impact of the bump. It doesn't need to be a pothole or anything like that, just a bump. To me it seems that when the vertical position of my front wheels change, the noise is affected. That is why I thought it had something to do with torsional vibration, seeing as how the half axle would be under torque from a different angle. Thanks for replying so quickly as well!
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Wednesday, December 10th, 2008 AT 3:40 PM
Tiny
BUDDYCRAIGG
  • EXPERT
I wouldn't expect it to be the injectors.
More likely a sensor that reacts to temperature changes.
There are ways of testing temp sesnors with a multimeter, a pot of boiling water and a thermometer.
A real time scan tool may be of more help.
I'm not talking about a code reader, I mean a scan tool.
Plug it in and you can see what the computer is "seeing", if the computer thinks that the engine is 195 degrees when you first start it, then the computer is going to use fuel curves and timing advancements that don't work so well when the engine is stone cold.
You do have a service manual for your car dont you?

A visual/touchie/feelie inspection of your suspension will probably identify the vibration/noise.
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Wednesday, December 10th, 2008 AT 8:33 PM
Tiny
KHAAN
  • MEMBER
Yes, I have a repair manual for my vehicle. Which section are you thinking might be of assistance? And is the real time scan tool something that a do-it-yourselfer could afford, or is it something that would be best to have a mechanic do? Also, what would be your educated guess as to the best place to do the looking and feeling of the suspension. Which part do you think would most likely be the suspect? I am thinking that it is the harmonic balancer still, I was hoping someone might verify that thought or at least agree lol. Otherwise I was thinking it might be a bad wheel bearing or hub. I already replaced both half axles because the cv joints were going bad, and that had no affect on the noise.
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Wednesday, December 10th, 2008 AT 10:05 PM
Tiny
BUDDYCRAIGG
  • EXPERT
I'm hoping that your repair manual may talk about testing sensors and tell you how may ohms the sensors should read at different temperatures.
Like it may say to test the sensor at 100F and it should had 50 ohms of resistance and then at 212F it should have 800 ohms. Something like that.

Scanning tools have come down a lot in the last 10 years. You can get a decent one for about $400.

The suspension noise could be coming from anything, it could be bad control arm bushings, wheel bearings, ball joints, struts, strut mounts. The list is endless. It really needs a "hands on" approach to find it.
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Wednesday, December 10th, 2008 AT 11:36 PM

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