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1991 Seville STS ,1992 Seville STS
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27 Posts
Discussion Starter · #1 ·
To start with I changed my spark plugs and wires today with Ac Delco Parts, Now my car idles and accelerates rough but when im at a steady rpm it is smooth.

I also noticed that there is a loud sound like a large vacuum leak near the back driver side of my engine.
 

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2011 Crown Vic LX, 2009 Chevy Malibu 2LT
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5,607 Posts
There are a number of vacuum lines back there, including the vacuum supply to the brake booster which could create quite a large leak. Track down the sound and repair the leak.
 

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2002 STS, 1991 Eldorado
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1,023 Posts
There are a number of vacuum lines back there, including the vacuum supply to the brake booster which could create quite a large leak. Track down the sound and repair the leak.
Agreed. Start there. May have removed the main vacuum line in reaching the rear plugs.
 

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1991 Seville STS ,1992 Seville STS
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27 Posts
Discussion Starter · #4 ·
ok found and fixed the vacuum leak. My car is still running rough and I dont know what to do.
 

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2002 STS, 1991 Eldorado
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1,023 Posts
Did you pull any codes?

The other thing you might want to do is check and make sure that all the boots are pressed firmly on the plugs and/or the plugs are tightened to the heads, just a thought...

If it ran good before the plug change, than it is more than likely something you did/didn't do...
 

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1991 Seville STS ,1992 Seville STS
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27 Posts
Discussion Starter · #6 ·
I have no codes, Ill double check over everything tomorrow when I get out of school
 

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1985 Sedan DeVille
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1,883 Posts
I had this problem when I did the plugs and wires on the neighbors Caprice. I decided to pull them all and redo the job (reset gap, reroute wires, everything), and it worked great on second try.

In my case I am pretty sure that I had too much silicon grease on a couple of the plug tips.
 

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58 Coupe Deville, 77 Coupe deville, 90 Deville
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184 Posts
If you still have problems after checking the above, distrubutor cap, rotor, module would be good places to look/replace.
 

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1991 Seville STS ,1992 Seville STS
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27 Posts
Discussion Starter · #9 ·
UPDATE!!!!!!!

Car will not start now
I went over the spark plugs and wires multiple times. and nothing
I noticed when enine was cool it would run good but when it got to operating temp it would start running ban and begin to feel like it had no power.

the only code im getting is a p052(history)
 

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2002 STS, 1991 Eldorado
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1,023 Posts
Look into your ignition control module and the coil; both can be tested at your local parts house. A failing ICM will give the previous symptoms mentioned...
 

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70 Deville 77 Fleet 78 Seville 92 Deville 03 Deville
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3,310 Posts
You need to check for spark at the plugs. You will need a friend to help with this. If there is spark then you need to check the fuel pressure. You will have to buy or borrow a gauge. Another way to check the fuel would be to dump a shot of gas down the throttle body and see if it fires. since this is the easiest i would probably try this first.
 

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1991 Seville STS ,1992 Seville STS
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27 Posts
Discussion Starter · #12 ·
everything fixed now, needed new cap and rotor, runs like a brand new car
 
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