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Discussion Starter #1
Hey guy my 1991 deville has a taking off problem and I don't know what it is. It smells like gas at the exhaust. I checked my FPR and no leaks or nothing. Any ideas on what it could be? I've replace the distributor and has a full tune up all the way around.
 

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92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
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835 Posts
Had the same problem with my 92 Fleetwood 4.9 FWD. Turned out to be leaking injectors. Common problem with 4.9's.

Start with diagnoStics, running then while you are driving. Monitor o2 , fuel trim etc to see if you are running rich
 

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White Diamond '03 DHS (with DTS floor shift)
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86,635 Posts
Pull the fuel rail with the injectors attached. Turn the key on to energize the fuel pump and pressurize the fuel rail. Look for a leaking injector.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,096 Posts
if the injectors are bad -
be sure to get the upgraded 4-hole injectors -

ebay has the best deal for replacements -
you can get a matched set of 8 - re-manufactured BOSCH injectors for around $100 -
 

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91 Fltwd Coupe (93 Regal Coupe & 90 LSC SE)
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426 Posts
I would suspect the catalytic converter is clogged, caused by fuel injectors needing replacement. Muffler and cat likely need replacement. Did mine with Magnaflow installed for about $290.
 

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Discussion Starter #8
There's times when it will run perfect that's what throws me off and I've had the cat replaced already.
 

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92 Fleetwood 2dr cpe - FWD, 96 Seville SLS, 02 Seville
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835 Posts
There is a power test that you can run via the hvac controls. It allows you to shut off each injector. When shut off, the rims should drop 50. If rpms don't drop, then the injector is leaking or not working.
 

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91 Fltwd Coupe (93 Regal Coupe & 90 LSC SE)
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If the cat hollowed itself out and was replaced, its insides would still likely be clogging up the muffler. Also if the muffler was replaced but the lines weren't blown out once the cat was replaced by starting the motor with the old muffler off, anything left inside the lines could clog the new muffler once the engine started.
 

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Had the same problem with my 92 Fleetwood 4.9 FWD. Turned out to be leaking injectors. Common problem with 4.9's.

Start with diagnoStics, running then while you are driving. Monitor o2 , fuel trim etc to see if you are running rich
How do you run these tests step by step. I have a 93 deville but I don't own the service manual. Along with the power test you speak of. Thanks!
 
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