Winstar woes(lack of power)

My original problem was lack of power. I knew some cylinders were not running because of a leaky timing cover gasket. I changed it, both upper intake manifold gaskets, spark plugs and wires, fuel filter and a few other small gaskets and o rings that came with the kit. When i started it, it idled fine and the timing was fine. I still had a lack of power. I could'nt get it over 80 km/hr and that took me 5 miles to do. I then had it to a small town shop that was a ford dealership not long ago. They told me the front cylinders were running lean and the back cylinders were running rich. They could not tell me what the problem was but hinted toward a possible plugged catalytic converter. I took it home and cut the pipe off before the converters. The lovely machine ran the same way. Yesterday I welded the pipe back on and I could only get 60 km/hr and when i got it in the yard it stalled. I now suspect the fuel pump but have no way to check the pressure. Can this be done without equipment? Any other suggestions would be greatly appreciated. Thankyou.

As you had the problem before, and you are suspecting the fuel system.
I would change the fuel filter to make sure that you do not have one that is clogged.
Then, I would run some good strong fuel system cleaner through.
I have seen BG-44 and Chemtool C-12 mentioned.
You add them to the gasoline tank.

The timing cover gasket should not cause a problem that would keep some cylinders from working. It can cause a VERY serious leak of coolant into the crankcase.....into the engine oil. Coolant in the engine oil can ruin your engine...(take out the bearings).

I would carefully check over the areas that you were working in to make sure that you have everything back together correctly. You did some MAJOR repair.....which, unfortunatley gives anyone doing the job a lot of chances to make a mistake.
Several things to check (assuming that everything for the timing cover part of the job is correct as that is a major teardown to just look at) would be making sure that the spark plug wires are going the right places (both ends), that the various plugs for all the sensors are plugged back in, and that the air intake is back together with no leaks. Double check the plastic line that goes from the opposite valve cover from the one that has the PCV valve .....the "breather" line....which should connect to the flexible air intake hose that goes between the throttle body and the MAF. You might try cleaning the MAF.

You might also try having the codes read to see what might be reporting as bad.