87 Brougham lack of power

I have an 87 Brougham 5 liter that has developed a lack of power. Timing is right, so is spark and fuel filter. Can anyone help.

Old air filter, worn camshaft or a blocked catalytic converter come to mind

Changed catalytic converter, and recieved some power back. Still lacking, someone said to remove carb and clean EGR passages, any ideas?

One more question, I did a test for timing but am not sure if I removed and plugged the right vacuum hose, where exactly is it located?

Changed catalytic converter, and recieved some power back. Still lacking, someone said to remove carb and clean EGR passages, any ideas?It's rather severe, but have you tried GM's Top Engine Cleaner? The instructions are on the bottle. Basically you pour this stuff slowly down the carb while the engine is running until the bottle is half empty. Then you pour the rest of it down and let it kill the engine. After a time (20 minutes, I think) you restart the car. I'd remove the new cat first, though :iceslolan.
Jeff

No, I have not tried that but will give it a shot. Thanks

I'm assuming you have a 307 under the hood, so I just hope you realize that 140 hp isn't nearly enough to move a 4000 lb car around very quickly. I have the same exact car and I can't get nuthin' out of it. The first time I stepped on it at a red light I thought I was taking off in 3rd gear! Anyway, If you do get any big improvements let me know. Good Luck.