1995 monte Z34

Have a 95 monte z34, and a friend let me borrow a computer analyzer, ( genesis systems with 2.0) gave me 3 error codes, PO134 HO2S ERROR, PO740 TCC ERROR, AND P1405 EGR SYSTEM VALVE 3. Was not sure if fixing all 3 was the answer, maybe 1 of these is causing the others to show up. Called for prices, and none of these are cheap way out, and it may need all 3, if not more. They say there are 2 sensors in the front of the catalytic convertor and 2 in back, front are $49.99 each and the back are $58.26 each. Could not get the TCC module or sensor whichever it is from the outo parts place, they told me to go to a trans shop for that. The last was an EGR System valve, which was $ 172.66, and all i got was it was somewhere on the back of the motor. So if anyone has some helpful info on this, would like to hear it. I have picked up some good info from this forum, changed out the turning signal, to fix that and the brake lights, had to remove air bag, and the info was great, Thanks.
The car has been starting fine but chugging, it still runs, but exhaust has changed tune, and the motor is shaking hard most of the time, drove it the other day and the gas pedal acted like it was pushing back, and took forever to get to 45 miles an hour, almost like somethings under the pedal but with nothing there.

The EGR Valve is probably just stuck. You can remove it by taking out the 3 bolts and unhooking the harness on the top of the valve. Its VERY easy to do. Take the valve off and unhook the sensor wire. Take a pen and push against the 3 butterfly valves slowly, some carbon will probably fall out of them. Put it back on (yes there is a gasket between the intake manifold and the EGR valve, make sure it seals good. Maybe also blow out the valve The EGR valve unit. Hook it back up and see if that was the problem.

The EGR valve looks like 3 cylinders that are stuck together, the sensor wire plugs into the top center of it.

Here is a pic of my 1995 monte Z34 EGR valve location (same as yours):

http://photos-b.ak.facebook.com/photos-ak-sf2p/v191/211/111/185106871/n185106871_32891505_9657.jpg