Leaderboard

I have LED headlights in my GMC truck. Recently I had to replace the battery because it went bad and wouldn't start the engine. Before the battery died I noticed my headlights were flickering some when driving at night and seemed to strobe when starting the engine, even in the daytime. After installing the new battery all the headlight flickering went away and almost all the strobing on startup. The LED lights have always strobed slightly since I installed them when starting the engine. When searching for the reason for the LEDs flickering and strobing I discovered that LED lights respond so quickly to voltage fluctuations it causes them to flicker if they don't get pure DC voltage. My alternator must have been straining trying to keep a bad battery charged and it showed up in the flickering LEDs at night. That's the only explanation I have for why it was happening when the battery was going bad. Your flickering lights might be telling you that you have some type of electrical problem like a bad battery, bad wiring connections or a bad alternator.

The one issue that can be hard to find, and that is bad data. It may not be far enough off to set a code, but a sensor out of spec can cause issues and this costs nothing to try, Simply unplug the MAF for example and start the engine under the same conditions the stalling occurs. If the stalling improves, it is a hint there is a fault there. It may not run well, but the stalling is the issue. Same can be done for the cam sensor, the intake air temperature and even the O2. Only one at a time and not immediately after each other. Does it help to add a little throttle in case the IAC is a little slow or gummed up?

I get my parts from ACKITS.COM in AZ. Any time I open a system, I replace the O-rings and convert to R134A. Need to find someone with a detector to find out where the leak is.

Secondary ignition problems (mine are all Delco now) - coils, plug wires, plugs - will not set codes. I do not recall ever having a EBCM fail. Try R&Ring the connector.

Noting beats proper instrumented troubleshooting.

Taken in Oak Ridge, TN several years ago.