94 bonneville has a loss of power and wont start sometimes?

Ok well i will describe the problems and maybe you can offer some help ... the first thing that occurred was a general loss of power and severe decrease in gas mileage. Also i noticed then it would idle roughly and when i only gave it a little throttle it would run roughly like it was sorta stalling. Well that was the beginning and since then the problem has worsened. I though maybe it was an exhaust issue, namely the catalytic converter so i bypassed it expecting the problem would improve but it has not .. Now sometimes it wont start at all. Once it has been from cold being turned off overnight and it would turn over but never fire, but mostly it occurs when the car has been running long enough to get to operating temp and i let it cool for more than ten minutes and try to start it again before 90 minutes or so. All i have to do when this happens is let it sit for an hour or two and when i return it will start right up. The one time it did it from cold that time was drastically reduced to only a half hour or less. The other thing that i notice is when i start it it runs poorly till it get slightly warm like i have to give it gas to keep it from dying, and also after an initial slight warm up it will idle ok till, from what i guess it the egr kicking open, ( i hear a click then suddenly it idles much rougher. I cleaned the injectors, bypassed the catalytic converter, changed all plugs and cables, replaced the fuel filer, and tried running higher octane fuels in case the injecters were the problem. Now im thinking it could be the fuel pump but i dont wanna just spend the outrageous amount to replace it ... like 199 for just the pump plus 30 for the stainer, without more info first. So any suggestions as to possible problems, possilbly how to test them and how to test the fuel pump without replacing it are all welcome help. Thank you in advance for your help.94 bonneville has a loss of power and wont start sometimes?I'd go after the cat converter. Try starting the car and get under it enough to look at the cat converter and if it starts getting red hot looking then theres your problem also look at the exhaust manifold(s) and see if that gets red hot. If its red hot like that then its the cat converter and it badly plugged up. A plugged up cat converter will cause the car to run very poorly to the point of stalling. Replace it at a modest cost of 300-900 bucks.