1994 Jeep YJ 4.0 5 speed manual - will run rough + speed odometer quits sometimes. new plugs,wires,distrubutor, cap,rotor,coil,02 sensor, crankshaft sensor. getting good fuel presure.

Lots of guessing.

old car, but is Chrysler made, good that. 93+

ok, the car has a cel lamp. is it glowing running\'?

this is called misfire. is the engine stalling?

on all cars that old the first thing do is check compression.



the rules to end misfire are this (a full tuneup)

fails

1: compression all the fuel and spark in the world can not run dead cylinders. ever.

2: then spark, check that all spark plug tips are clean and the spark is strong. then check timing, if any thing here is wrong fix that next.

3: fueling this is complex and is always last. after spark.

I6 4.oL is nice motor owned 3 since 1988. zillion miles on them.

unlike 88s your\'s dont suck. mine had horrid french RENIX EFI......

nasty that..... is...



so you do the flash test on the CEL yet, see if you have DTCs stored.

if not why not? this be like first. its free, and is very helpful

if you have DTCs/ stored. DIag mode is activated with.



put the key in the ignition and turn the key to run (not start), then off, then run, then off, then run (that\'s 3 runs and 2 offs). Leave the key in the run position

count the blicks, best done just after misfiring.





fueling is complex.

6 injectors that can leak ,or clog.

the test is called a injector balance test. but is never done

before the 3 fuel pump pressure tests and the 2 regulator test

never. are those to be skipped and the tool is $20 lousy bucks.

if you get this far , we can do fueling all day. long.

but we also check all sensors for valid inputs.

as all ECU puke with bad inputs, all computers for that matter







saying good fuel pressure means zero with EFI, ZERO

only PSI matter.s not squirt tests. or other dribble tests.

those only proves pump is not 100% dead.