Help! 1998 Stratus won't start, complicated.

Hello, all. A friend of mine was driving his 98 Stratus (2.4) on the
hiway when it suddenly quit. I towed it to another friend's place
(who is a mechanic) and he looked it over and hooked up his Snap-on
computer to the car. The battery is fully charged, the engine turns
over rapidly and smoothly, the injectors are firing, fuel pressure is
good, but there is no spark whatsoever. Using the computer he can
make the coil fire (both sides of the coil), so the on-board computer
can control the ignition and make it fire. The computer recorded
"lost sync" with the crank position sensor and the cam shaft sensor,
but replacing both of those units made no difference. The computer
still reports "lost sync", and the cam shaft position sensor feed
seems to be intermittent (the computer reporting connection:
Yes...No...Yes...No, and so on). I found two chassis ground lugs
under the hood where a pair of wires runs to each location and cleaned
the grounding spot and re-attached the ground wires. I also cleaned
the contacts on the ground strap that runs from the top of the engine
to the chassis. We've also checked the timing belt (it's intact), and
made sure the cam sprocket marks line up on TDC (they do).

Any ideas?

TIA

--HC