Brand new member here!
My 1999 CL was not heating up, so I replaced the thermostat. Now it heats up fine, but it started running rough the next day and popped multiple codes (P0300, P0302, P0305, P1399). I do have 360,000 miles (hooray!) but I can't help believe that something I did caused the problem. Is it possible a poor connection on one of the wiring harness/ connectors could cause this problem? I had to disconnect 3 or 4 and I did spill a little coolant.
My 1999 CL was not heating up, so I replaced the thermostat. Now it heats up fine, but it started running rough the next day and popped multiple codes (P0300, P0302, P0305, P1399). I do have 360,000 miles (hooray!) but I can't help believe that something I did caused the problem. Is it possible a poor connection on one of the wiring harness/ connectors could cause this problem? I had to disconnect 3 or 4 and I did spill a little coolant.