Thanks for helping me with my truck!
The main issue is engine hunting upon cold starts- the RPMs oscillate and the check engine light goes on and off.
In addition to when you hear the engine start in the morning, I hope these videos will help. Listen closely to the audio, and note the check engine light. My feet are off the gas and on the brake throughout the videos.
This problem started happening after the clump of wires to the right of the passenger’s feet were partially submerged in water overnight (that’s when I decided to drill the hole in the floor 🙂 ) That happened a few months ago.
After driving it for a few seconds, the engine light would turn off and the engine performed normally. However, after leaving the truck parked for five weeks, the engine hunting was much worse the first time starting. While oscillating, the RPMs would go very low, and the engine light would not turn off. Driving the vehicle reduces hunting, but the engine light remained on for several minutes that first time I drove it after the five weeks of disuse.
To prevent predetonation, I’m using exclusively premium fuel, with a bottle of octane booster in every tank.
See recent vehicle servicing history for relevant information on spark plugs, spark plug cables, and EGR system servicing.
Also, I am losing about a quart of engine coolant a month. Please check to see if there are any easy fixes, but please don’t spend too much time on that.
6 Mar 2018