im new to this so bare with me buy I have a 95 buick riviera sc my car runs like its brand new while cold but once it heats up it so sluggish change fuel system and cooling system still the same.... im clueless

Unplug the MAF and see if there'* any difference, if not, plug it back in. Check the EGR, it might be stuck open. How does the engine coolant gauge look? If that'* not moving like it should the coolant temp sensor might be bad. have you checked the air filter?

well it stays at a good running temp but can fell through hood some times I changed thermostat and hoses. put cold air intake on it last week so air filter is new never checked temp switch though or egr ... last month I flushed cooliant and it look like cooliant was all in block nothong in resvior every but I can hknow I put the requured amount in system also changed water pump last summer