About once in every five times i drive my 2000 GMC Jimmy, it keeps
running after I turn the key to the off position. The dashboard goes
out (all of the gauges stop working, too) but the engine keeps right
on running. The first time this happened I pulled the fuse to the ECM
and it stopped right away.
Here's the really odd part: out of desperation, I tried every button
in the cab the next time it happened. Lo and behold, turning the
hazard light on and off kills the engine. I also noticed that
sometimes I'll have my foot on the brake when I turn the engine off,
and the engine will keep running until I take my foot off the brake.
This may be related, I don't know: the right turn signal comes on an
stays on (doesn't blink). I tried replacing the blinker module behind
the glove compartment, but that didn't change anything. Left turn
signal works, and occasionally blinks fast like there's a bulb out,
then goes back to normal after a while. All the bulbs are fine.