Picked up a '96 Cherokee a few weeks back and finally have time to tinker with it. It has a rough idle with a CEL. The codes where:


P0204
P0202
P0302
P0304
P1492


I went ahead and put new OE spec plugs and wires on it. As well as 2 new injectors in. At idle, I can unplug injector #1,#2,#4 without a change in the motor. Only getting a code for P1492, Ambient/ Battery voltage too high. Still has a rough idle and gets slightly better at 2,000 RPMS driving down the street and back.


Take a second to start when turning the key. Followed by a violent shake/stumble and slowly idles up to 750-875. Not sure if I should replace the coil/ distributor next. Passed a compression test without leaking down.


Going to clean out the distributor cap and reinstall to see if it helps any. has 194k original miles. Sounds almost like it bogs while under load. Like I'm pulling a 20' enclosed trailer.


Also going to check out how the catalytic converter looks since I hear a rattle somewhere down there from the muffler or cat???

 

Pull the battery and check the sensor for corrosion, poor connections, or bad wiring. Should be a spring washer between the sensor and tray, allowing the sensor to move up and down. Forget where i read this, but resistance was said to be between 9k-11k ohms. I would also check the injectors with a noid light to see if they are even doing anything, just because i could, as you may have more than one issue. For the rattle, check the exhaust as it passes over the transmission crossmember. If they are touching, the transmission mount is likely shot. As for the cat, check the heat shield as the tack welds can break, and the heat shield rattles. It can sound just like a broken cat.

 

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There is corrosion in there from a radiator hose splitting.


Trans mount is new. Exhaust is in tact. I only hear the rattle when it idles around. 300-450 RPM. I can go under the muffler and smack it with a mallet and here something moving around.


I have a power probe only atm. Wondering if I can unplug the coil wire and spin it over and still get some sort of voltage reading off of it

 

No, you should not. You should stop firing the parts cannon and do some thinking and some testing.

What possible connection could there be between a couple of injector fault codes and the coil or distributor?

Let me answer that question: none.

Those codes are there for a reason. Follow up on what they have told you, and you might get some results.