Need expert advice! 91 Cherokee Laredo 4.0

Hey guys, been having and ongoin problem for awhile now. During the symtoms of this problem a have replaced head gasket, distributer cap, wires, plugs, fuel filter, ingnition coil. Cleaned most grounds ( all I can get to anyways), origanally changed CPS witch helped but has yet to solve the issue. The only time this problem accurs is when I'm slowing down for a stop sign and illegally run through( kinda ironic), but will stall and not fire back up until battery is almost dead, or won't fire at all until I mess with something random ( or just let sit for a couple days. Mind you I've replace CPS twice as well as fuel filter.

When it dies and won't restart, does it turn over but not catch, or what? Does it have spark? What is the fuel pressure when cranking?

These are two things I have yet to check after stalling in the middle of an intersection but when back home there is spark and very strong pressure on the rail. I want to buy new injectors and fuel pressure regulator but not both. Jeep has 216 thousand miles but looks well taken care of.

But yes it turns over and over

Harmonic balancer looks very ill and has a constant squeal

The orange wire going into the CPS should be the sensor power *in* wire (best guess on the color as I have no diagram for the 91). The CPS shares the voltage input with other sensors, the Cam position sensor and the speed sensor. Often when you get low sensor voltage to the CPS it is the Cam position sensor partially shorting out, sometimes the CPS itself or even a dirty connector (oil or coolant covered connector).

An oil soaked CPS can also mess up, usually from a leaky valve cover gasket.

I'm not sure what the CPS input voltage is supposed to be for the 91, best guess is 8 volts for the early non Renix XJ's.

You may also want to do an ohm test from the black wire (with a stripe) at the CPS to the battery negative terminal.

All tests should be with the connectors still connected for the most reliable voltage readings.

Time to test the grounds, the TPS the IAC and the IAT sensors and controllers?

Check the vacuum line to the MAP sensor?

Is the spark good and hot? If not the HV coil or ICM module may need cleaning on the contacts.

Might check the O2 sensor wire, sometimes they can flop against the header and short out

Could be one of the other sensors/wires/connectors. When I changed my serpentine belt on my 96 last fall, I unplugged the sensor wire that was in the way of belt tension bolt.

I forgot to re-connect the connector and my beast refused to start. Plugged it back in and it ran rough for a little while and then came out of it.