My 1994 Jeep Cherokee (Inline 6 4.0) started running really rough last
week as if one of the cylinders was missing. I changed all the plugs
and wires and cap/rotor and that fixed nothing. I was thinking maybe
an injector wasn`t working and turned the Jeep on and unplugged each
injector one at a time. Unplugging 4 of them made the engine start to
die off right away but the #2 and #3 injectors didn`t seem to change
anything when I unplugged them. So I figured those injectors were dead
and replaced them. No change again. Still running really rough. (I
know it was stupid wasting money but I really needed to try and get it
running as I had a trip down the highway I had to take on the
weekend.) I finally got tired of messing with it and took it to a
repair shop and the guy there called and told me, "There`s no
compression in those two cylinders." To make a long story short I just
told him to leave it alone and I`d come pick it up. But today I was
off work and went out to mess with it and I unplugged and removed the
2 spark plugs for those 2 cylinders (They were black with soot) and
when I fired the Jeep up there was a lot of air being pushed out of
the plug holes as the engine stroked. So I guess my question is: Isn`t
that compression? I`m trying to eliminate possible simple fixes before
junking this thing. Thanks for any input.
