2000 Cadillac Seville Hesatates when given gas

2000 CADILLAC SEVILLE
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JHINES037
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2000 Cadillac Seville V8 Two Wheel Drive Automatic
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The car had the transmission rebuilt not to long ago and worked fine for a while. Now iwhen you give it gas lightly or go up a hill it hesataes and shakes a little when you give it more gas or floor it it stops. We think it might be the trans mission but it shows no codes and does not happen all the time. Yesterday morning when it was first cranked it ran rough and when my mother gave it gas it stopped and black smoke came out the back. hope you can help with this problem
Jul 22, 2008 at 5:56 PM
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SERVICE WRITER
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The black smoke is a sign of a rich condition.

How many miles on it? How old are the plugs and wires?

What type of driving do you do? That is, is it driven enough and often enough for the temperature to come to operating temperature? Short trips can cause this.

There may be enough carbon on the front oxygen sensor to make it lazy, but not bad enough to set a code. This can be scoped.
Jul 22, 2008 at 8:13 PM
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JHINES037
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Its got well over 125000 miles and not sure how old the plugs are car was gotten froma good friend of my mothers and it is driven every day for my mother drives it to and from work so it has time to reah op temp
Jul 22, 2008 at 9:02 PM
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SERVICE WRITER
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Check with the previous owner and find out how old the plugs and wires are. Might want to pull one regardless and check the condition. Check the wires for any routing issues that may be shorting a wire or causing a crossfire.

Also on the maintenance end, a plugged air filter can cause a richer condition.

There is a TSB on Plugged fuel injectors, but the carbon makes it sound more like too much fuel.

Check the fuel presure, if the regulator is weak, too much fuel can get unburned.
Jul 23, 2008 at 5:30 AM