Three quick items of business.
1.) I'm not a mechanic
2.) 2010 Malibu is step daughters car (in college) so I have driven it very few times
3.) I have never posted to any forum before
This car, since the time of purchase from a neighbor having 50,000 miles, has intermittently given the service traction and service esc messages. In the last 8 months or so she has complained about a minor hesitation during idle that has increased in intensity and frequency during idle, acceleration, and cruising, highway speed with no check engine light or codes So.....
1.) months ago she was in for the weekend and I changed the oil, air filter, spark plugs, and ran a tank of better fuel. No change
2.) I won't bore you with the details of why each step or order necessarily, but this week I did the following:
A.) new boots and fuses on spark plugs
B.) installed new CMP sensor
Problem got a lot worse. Very rough idle, persistent traction control messages that were intermittent, and p0201 and p0301 error codes (misfire cylinder 1). So.....in no particular order.
C.) new plugs again
D.) verified with inline light that spark plug was getting what it needed
E.) exchanged all spark plugs and coils from cylinder 1&2 and 3&4, verifying proper torque
F.) removed and externally cleaned all fuel injectors and exchanged them between 1&2 and 3&4,verified resistance of each fuel injector, and input voltage on cylinder 1
No change. Error codes cylinder 1, rough idle, traction control messages remain unchanged.
G,) compression tested all cylinders (dry test. Had uniform compression
H.) looked for vacuum leaks
I.) reset PCM
No change. Ready to throw in towel.
Read this post. Decided to get more aggressive on wiring. The black wire on the fuel injector for cylinder 1 was visually fine and passed voltage, but it was kinked and the internal copper was barely making contact in 2 places within 3 inches of fuel injector 1. I cut the wire,stripped the end and, and forced the stripped end into the harness as best I could. Fired the car up, smooth idle, smooth acceleration, no error codes and traction messages gone.
Replacement wiring harness for fuel injector 1 should be here today at noon. It may be coincidence that the traction control messages stopped, but I'm confident that the rough idle, hesitations, and error codes are resolved by removing the bad portion of the lead wire on fuel injector one.