thanks in advance for any help. here is my problem. I have a 98 blazer with the 4.3 4x4 and i started getting a P0118 code which is for the coolant temp sensor high input. i replaced my coolant temp sensor between the #3 and 5 plug with a brand new one and now my truck runs worse than before. The check engine light comes on and my temp gauge bounces all around or just sits at 100. the truck sputters and stalls at times. can anyone help me out with what may be causing this problem/

 

Sounds like you might be experiencing a wiring issue. Try testing all of the wiring noted in the link below. If that doesn't work, go through the diagnostic steps.

P0118 - Engine Coolant Temperature [ECT] Sensor Circuit High Voltage

 

would my battery not being very good cause any of this. My battery is very weak and i was just wondering if that could cause this issue as well