If one inj is spiking high, then it has too much resistance
in the circuit or is possibly clogged or partially. You can
do a drop RPM test. Pretty easy. Get it to idle and
then pull each plug wire from the plug for just a couple
of seconds, make it quick. When you pull a wire,
listen for the RPM to drop. If it does that's a good
cylinder and is firing. When you come across one
where you pull the plug wire and you get NO drop
in RPM then you've found your bad cylinder.
I'm not sure on this, but I believe you can so the
same to the inj plugs, but you must be pretty quick.
Get it warned up and idling. Then pull each inj
connector from the inj and see if you get an rpm
drop. If you do, then that's a good cylinder and
is firing. When you come across one where the
RPM doesn't drop, you've found your bad cylinder.
I just received my service manual from a seller
over at eBay. It is massive. At least 3" thick and
appears to have everything about a Lumina in it.
I'll go through it to the troubleshooting misses, etc,
and see what is avail which I'll post you want.