So my 2008 Saturn Aura goes into I guess it's called limp mode after I drive a couple blocks it only happens when it's hot outside and usually I can pull over and let it cool off for a little while and then I could start it up and go again another couple of miles and then it does the same thing can now the codes that are coming up or the 0455 which that code was already coming up before I even had the problem and then po128 po325 PO420 po1682. So is the po128 is that the thermostat and would that cause it to go into limp mode? The only thing I've changed out is so far was the variable valve timing solenoid actuator I think it's called the intake one and I have not changed the oil yet would that make a difference all the fluids look like they're fine except the oil does need to be changed which I plan on doing today. Of a family camping trip coming up in a couple days and I really need to get this fixed any help would be appreciated

 

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