The last few months, I've been trying to track down a P0118 (Engine coolant temp sensor high voltage) and P1115 (Engine coolant temp sensor circuit intermittent high voltage) on my 97 K1500. I first replaced the ECT sensor up top, which worked for awhile, but developed a bad jerk when accelerating. In October, I replaced the connector, and that took care of the jerking. This morning, the CEL came back on a few minutes after startup, and again it showed the P0118 and P1115, along with P0161 (O2 Sensor heater B2S2). Is the p0161 related in any way to the ECT circuit codes, or am I just chasing my tail again?
Another issue I've been dealing with for awhile:
The truck also has an intermittent hard/weak start after sitting for a few hours or during normal drive cycles (going to stores, work, etc) It does NOT do this after sitting overnight or longer. When starting for the first time in the day, it fires up perfectly. I tested fuel pressure, which seems ok (57 psi, IIRC). Pressure does drop slightly when I pinched off feed and return lines at fuel pump, but not drastically or at a fast rate. I did replace the original spider injector system with the upgraded MPFI system last March, and fuel pump in May 2022. The fact that it'll start right up after sitting for days at a time makes me think it's not fuel related, but I have no idea anymore, I've been wrong in just about everything I've tried to fix on this truck.
Another issue I've been dealing with for awhile:
The truck also has an intermittent hard/weak start after sitting for a few hours or during normal drive cycles (going to stores, work, etc) It does NOT do this after sitting overnight or longer. When starting for the first time in the day, it fires up perfectly. I tested fuel pressure, which seems ok (57 psi, IIRC). Pressure does drop slightly when I pinched off feed and return lines at fuel pump, but not drastically or at a fast rate. I did replace the original spider injector system with the upgraded MPFI system last March, and fuel pump in May 2022. The fact that it'll start right up after sitting for days at a time makes me think it's not fuel related, but I have no idea anymore, I've been wrong in just about everything I've tried to fix on this truck.