I have a 1998 Ford Ranger (4 Cyl, 2.5L, Manual Transmission) that I
bought used a couple years ago. It's been running fantastic other than
a little burp here and there.
I recently took it to a Super Wal-Mart to get the oil changed, and I
opted for the "signature service" package, which they're suposed to go
in check other fluids and whatnot, other than just the oil.
Almost immediately after getting my oil changed, I noticed that every
time I started braking that the truck would shake and shudder like it
was about to stall. It would do this for a few seconds, and then would
go back to normal. This happens consistently, regardless of coming to a
hard stop, or a gradual coasting stop. The truck will also shake and
seem like it's about to stall if I'm sitting idle for a period of time.
I have also noticed that doing a low-speed hard turn will also cause
the truck to shake, and has in fact caused the truck to stall out
completely. I have stalled three times in as many weeks, once from a
low-speed turn, once from a hard stop, once while driving.
My dad thinks it could be the timing belt, but I've also read ideas
from others with similar problems that it could be a air intake valve
or something like that.