Hello, Im having severe power loss in my Chevy Beretta. Driving normally down the street, it works fine, excelerates just fine on flat roads, but hill at all kills it, i can barely make it to 35 mph in canyons I used to cruise at 70. The fuel pump has been replaced very recently. Any ideas?

I have a 2003 Toyota Camry, I4 engine, about 100,000 miles, recently "check engine" light came on. Got the OBD code P0420 at AutoZone, and the possible cause, from AutoZone printout, could be: 1. Engine misfire or running condition 2. Large vacuum leak 3. Engine oil leakage The car did not have any major service except for routine engine oil and transmission oil changes. The spark plugs looked better than I expected, considering 100K milage (slightly worn tips, light yellow color and no excessive deposit), but I changed anyway. The oil level maintains constant so I don't think oil leaking is the cause, neither. This lead to only possibility of "large vacuum leak". However, I don't have any experience on this. If this is the case, what kind of symptoms you would expect to see and how to check and fix the problem? Any inputs are greatly appreciated.:confused: