1990 deville missing

[chevyman1971]

It runs perfect until it gets hot then it starts to miss and it wont idle right.it loses alot of power,it feels like as if you would pull 1 of the plug wires off and try to run it
I have replaced the plugs,wires,distributer cap,rotor button,ignition controll module, coil, fuel pump, fuel filter
and also i just bought the car and it has only had about 300 miles put on it since 2009

if anyone can help thanks

i checked for codes but there is none

i also just noticed that the exhaust is getting super hot, it seems like its the whole exhaust, i ran it about 3 miles and it was like this

[maxwedge]

If it is a dead miss, you could kill one cylinder at a time until the one that does not change the rpms is the suspect cyl., then look at that plug/wire. If it has good spark, do a compression test. Also watch for any vacuum leaks although temps would not affect that.