Help me diagnose my Fiencee's buick

[Don87LX]

Ok. 92 century, 3.3 FI v6. This car used to be crazy fast, but has lost lots of power slowly. NOw it is to the point that my honda can absolutely slaughter it from a standing start. The spark plugs are ok and it is not missing a cyliner. The timing is ok. It idles nice and smooth. when you hit the gas it stumbles and studders until you get over 25 miles per hour and then runs smooth but still lacks power. I thikning either and injector may be getting bad or possibly the cat converter has collapsed. I have no clue when the fuel filter has been chenged, the air filter is clean. help me out guys.

[Sean]

does it have a mass airflow sensor ???? tryt cleaning the throttlebody as well. also clean the MAF sensor if it has one. check yr fuel pressure and REPLACE THAT FUEL FILTER. go back to the tank and look on the rocker panel just before rear wheel on the driver side.

[ACCORD EX]

does it have an idle mixture screw ! my car used to do that when it the Air / fuel mixture wasn't set correctly !

MIKE

[smufguy]

okay this is a crucial part huh? your fiencee's car. man........ talk about a great test in life. so anyways, seems like her car is running rich. cars usually stumble until they hit like 2.5K or 3k if they are running rich. If it idles smooth and stumbles like crap when u hit the gas, its really something new.

here are the mightbe reasons for our cars and see if u can work it on her car with this info

for engine stumbling on acceleration

1. Spark plugs fouled
2. Fuel injection system needs adjustment or repair
3. fuel filter clogged
4. incorrect ignition timing
5. intake manifold air leak

the other reasons i might think of is to check out her distributor. but some or most GM cars dont have one, and they have tech. they are these ECU controlled piece of solonoid junk, that my mechanic seems to like . how much miles is it on her car? get a tune up . thats far as i can go with the domestic, cause after around 115K or 120K they are honestly a piece of junk.

[Don87LX]

After futzing with it I am pretty sure that the cat is clogged up.