I have a Toyota that has had some problems lately with fuel injection & starting. It has yet to be nailed down, but it's most likely something causing an extreme lean mixture, preventing ignition and eventually flooding the engine. I think it's commonly referred to as the 5o'clock surprise because it usually happens in the afternoon, after sitting a couple hours since the last time. It rarely happens in the morning.
Anyways, I thought I'd mention that before I move on the the knockin/poppin because I have no way of knowing if these problems could be related or if one is causing or a symptom of the other.
The popping sound quite a lot like a ping pong or tennis ball. It starts up if the truck has been idling for a while or if I've been in start/stop traffic. It is steady and at about 1/2 sec intervals - doesn't change with throttle but changes slightly with idle rate. Sound is emanating from the right-center rear of the engine.
Here's the kicker. If I turn on my dome light inside the cab, the sound stops immediately. Not headlights, not brake lights, just the dome light. Turn the light off again, the sound starts back up immediately.
Am I hearing the sound of an electrical arc? If so, could this be affecting my ignition system?
Thanks!