Ok Guys I need help with my 2001 2.7L Not getting warm enough

My check engine light came on and it's giving me a po125,p1130,p1135 codes. Now auto zone says it could be the thermostat or coolant level or old coolant or ICM. So I replaced the thermostat and the coolant with all new stuff and the light came back on, But I noticed after I had replaced the thermostat and got all of the air pockets out and ran it down the road I checked the upper and lower hoses for heat and the upper one was very hot and the lower one pretty cold compared to the upper hose. So I drove it for 15 miles to see what happened and it was still cold. The gauge reeds a little above normal and it's not over heating. So WTF is wrong here guys??? I'm at a loss here, has anyone had the same problem? If so tell me what to throw at it next.

Thanks
Dave

 

If the upper hose is hot then the thermostat is opening up and letting the cooling system work. Perhaps it is the coolant temp sensor that is going bad and not letting the ecu read the correct temperature.

 

Sean,
Would that be the sensor that is located on the backside of the engine against the firewall, You know the one that's a bear to get to?

 

I have a 2.7 but I believe the temp senser on the v6 motor is on the back next to the firewall.

 

Forgive me if I'm misunderstanding what you're saying here, but this is completely normal. The upper hose contains coolant coming from the hot engine, and the lower hose is that same coolant after it's been cooled through the radiator (that's the radiator's pupose, after all) on its way back to the engine to regulate its temperature. Those hoses better be significantly different from each other after the engine's been running for a while. If they were anywhere near the same temperature, that would be indicative of a problem.