Just did a junkyard engine swap on my 2007 2.2(slipped timing ... Anyway, I'm in I guess what you'd call the debugging stage, and my coolant temp sensor is going insane! It will fluctuate 104/106 when just idling after starting, once I start to drive the car holy moley does it go nuts, I'm talking 169, to -11 to 298, straight bat sh*t nuts... So I replace the coolant sensor and t stat, no change with the new sensor, still acting like my mother in law.. So now I'm assuming wiring, but A) I do hvac for a living so I'm good with basic electrical, but damn I have no clue where to begin or how to test for shorts nor I do I know what connections are related with the sensor, obv ones are the from the sensor to the I believe it's the PCM or ECu correct me on it but the brick that sits in front of the fuse box in the engine housing, but I visually inspected those, trace the ground coming off that its a black/white stripe running to a bolt on the tranny seemed ok, so I can only believe that wire has to run to something else that I can't see... My only other thought on it is when I changed the t stat and the sensor I never purged the system, to be honest I didn't purge it when I swapped the motor and my only second thought is there's a crap ton of air in the system and it can't read temp... Let me know you're thoughts PLEASE AND THANK YOU, oh and not completely off topic but my speedo doesn't work, I have the 5spd trans and It worked before the swap, I can see that sensor as well and I'm almost wondering if these problems are somehow related due to them obv both being on the gauge cluster.. Again please gimme you're thoughts!