A month ago, I fired up the lump (cold) and it went "POW!" similar to that of an Anchor Brand 1 1/2" firecracker, (you remember those: "Do not hold in hand -- Lay on ground, Light fuse, Get away quickly).
For the last four weeks, after starting, the idle would fall from its cold 1800rpm level to its "normal" 900rpm, but then would strangle down to 400rpm, only to bounce back up to 900rpm repeated. Tapping the throttle during this bit would emit backfires, (not as loud as that first one, but I could literally "feel" them through my shoe on the pedal).
Now I've just come in today from a 15-minute drive, and the condition has cleared, no idle bounce, (steady again at 900rpm), nor backfiring whatsoever.
Of course, I'm expectant that whatever was wrong may recur: Any ideas of what's going on would be appreciated
Something electrical perhaps, (plug cable?), or a temporary "clog" in the fuel injectors?
Best to the "group".