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Weird problem, 95 LT1

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Old Sep 22, 2008 | 08:30 PM
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St. Jude Donor '07-'08
Default Weird problem, 95 LT1

This just started today. Was running some errands earlier, had been driving around for about 15-20 minutes when I got to the store. When I left the store I was sitting at a red light and the oil pressure dropped to the line before 0. The ac was running and all the temps were normal, the idle was normal but when (I'm not a mechanic so I don't know how to accuratley describe) the alternator would run the idle would get rough and make a thud noise and shake the whole car then go back to normal. I turned the ac off and it continued. Driving is normal and there is no problem. I even put it in park and at idle everything is normal. It just happens while in drive with my foot on the brake. When I got home I let it sit for about 3 hours and went driving. Again everything was normal until I'd stop at a red light and it would start. Has anyone had a similar problem? And if so what was going on?
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Old Sep 22, 2008 | 08:46 PM
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Could be the alternator acting up. I had an intermittant problem with mine. When under heavy load it would drop below 12 volts and cause some crazyness.
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Old Sep 22, 2008 | 09:04 PM
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Originally Posted by dudman
Could be the alternator acting up. I had an intermittant problem with mine. When under heavy load it would drop below 12 volts and cause some crazyness.
The volts stayed normal as well. I don't know whats going on. I didn't drive or do anything out of the ordinary.
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Old Sep 22, 2008 | 09:06 PM
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How would you know when the alternator is running. Are you confusing it with the AC compressor?
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Old Sep 22, 2008 | 09:18 PM
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Originally Posted by MK 82
How would you know when the alternator is running. Are you confusing it with the AC compressor?
It was probably that, actually now that you say AC Compressor I'm pretty sure that is what I was hearing. I shut the AC off (completely) and it was still doing it. Sitting at idle in park it doesn't do it. Only when in drive with my foot on the brake.
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Old Sep 22, 2008 | 09:21 PM
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How old is your battery? How many volts are you showing? Should be more than twelve 13-14. What I hear you saying is with your foot on the brake you had a problem but in park you didn't. Also, turning off the AC reduced the load. I'm not an expert by any means, just had those type issues with mine.
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Old Sep 22, 2008 | 09:35 PM
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Remove Throttle body and IAC, Clean and reinstall same.
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Old Sep 22, 2008 | 09:35 PM
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Originally Posted by dudman
How old is your battery? How many volts are you showing? Should be more than twelve 13-14. What I hear you saying is with your foot on the brake you had a problem but in park you didn't. Also, turning off the AC reduced the load. I'm not an expert by any means, just had those type issues with mine.
Not sure about the battery as I've only had the car a few months, the voltage was in the normal range and more than 13-14 but not near 18. Yes, this problem only occurs while in Drive with my foot on the brake, happened everytime I was at a red light. In park the idle and everything is normal, including the ac compressor. But it still does this with the ac off.
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Old Sep 22, 2008 | 09:37 PM
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Originally Posted by MK 82
Remove Throttle body and IAC, Clean and reinstall same.
Whats an IAC?
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Old Sep 24, 2008 | 04:17 AM
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Originally Posted by MK 82
How would you know when the alternator is running. Are you confusing it with the AC compressor?
Well Considering that when the engine is running and your belt is not broke the alternator is always running!
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Old Sep 24, 2008 | 07:46 AM
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I think everyone saw 'alternator' and is now trying to help with a voltage issue. However, your original post says 'oil pressure' - did the oil pressure light come on? Can you describe the thud noise or do you think it is the AC compressor switching on and off? Also - does the oil pressure go up when you rev the engine?
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Old Sep 25, 2008 | 08:06 AM
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IAC [ Idle Air Control valve] under the throttle body on the LT 1 .
Also check and replace air filter.
Read codes first before doing anything.
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