2002 Pontiac Firebird Rough Idle when wet, no engine power

Tiny
GARYTHFLA
  • MEMBER
  • 2002 PONTIAC FIREBIRD
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 181,000 MILES
Whenever my car's engine gets wet, it starts idling really rough and the I don't have much engine power and the "check engine light" comes on. It doesn't happen when I first crank the car (for example, in the morning) but when I go home at night, it's pretty bad. I also have a little bit more smoke coming out the exhaust than I think is normal, but that was just when I first cranked it up this morning.

background information.I just put a new throttle body assembly on it and the transmission is only 2 years old. The fuel filter is only a few months old as well. The fuel pump and water pump are only 2 or 3 years old and the alternator is brand new also(less thank 6 months old). I also just had the spark plugs changed.
Friday, August 28th, 2009 AT 12:58 PM

6 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Were the ignition wires replaced when the plugs were?
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Saturday, August 29th, 2009 AT 12:24 AM
Tiny
GARYTHFLA
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  • 4 POSTS
No, the ignition wires have never been replaced.
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Saturday, August 29th, 2009 AT 8:16 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
That would be my first guess. At night (in the dark), open the hood and start the car. Spray a mist of water over the plug wires to see if they arc (spark) when wet or damp. That could be the entire problem.
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Monday, August 31st, 2009 AT 8:39 AM
Tiny
GARYTHFLA
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  • 4 POSTS
I bought some new ignition wires and put them on and the problem seems to be getting better. It still idles rough but not as rough as before.

I'm wondering if it will gradually get better as I drive it or if there could be another problem.

The check engine light is still coming on when I drive although I seem to have have regained some of my lost power. I had my car hooked up to a computer on saturday and it said cylinder 3 wasnt working like it was supposed to.
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Monday, August 31st, 2009 AT 9:48 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,176 POSTS
Did they reset the light? And if they did, has it come on again? If so, have it rescanned to see #3 cylender is the problem. If it is, I will advise you on what to do next.

If they didn't reset the light, have it done. Most parts stores will do it for free.
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Monday, August 31st, 2009 AT 10:28 AM
Tiny
GARYTHFLA
  • MEMBER
  • 4 POSTS
They didnt reset the light and it will be this weekend before I can get back over there. I dont think having the check engine light reset will cause the rough idling to stop but I will ask them to do it.

Like I said before, it is running much better but still somewhat rough.

I'll send another reply when I get the light reset and let you know.
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Tuesday, September 1st, 2009 AT 7:05 PM

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