My 98 5.9 grand cherokee started acting odd yesterday. Occasionally,
from a stop it would be real sluggish about taking off and sounded a
bit odd...almost like it wasn't getting enough gas. Then it drove ok
for a while, shut it off and started it back up. CE light was on so I
pulled the codes. I got these:

PO726 The PCM has detected that the voltage signal from the engine
speed input is out of range for the current engine operating
conditions.

And:

P1281 Injection control pressure out of range high.

Any ideas?

Never came acroos anything that involved before, usually simple stuff
that I can diagnose right away, but I'm kind of aprehensive about
driving it without knowing what's going on.

Any help is GREATLY appreciated.
TIA

Mikhail