Multiple Cylinder Misfire, HELP?

So I have had the same re-occuring problem for a while now. I have the 97 Sport with about 125k on it and my engine light is on. We hooked up our code reader and I am getting multiple engine misfires on a couple different cylinders. Sometimes when I am driving it seems to want to quit out on me when I am in 1st or 2nd gear. Those two gears are the only time it ever happens, and when it does all I have to do to get it going again it take it out of gear and give her a little rev to clear her out and its fine again. I thought it might be the cat so I replaced the whole exaust and the O2 sensor that screws intot he cat and the light went off for a while. Now it seems to come on and off every like month or two. On for a month and then off for one. I continued to replace the plugs, distributor cap, and wires to no avail.

Anyone ever had anyting like this happen to them, some help would be great. I am kinda stuck.


EDIT: The name of the thread should be Multiple Cylinder Misfire, my b.

Re: Multiple Engine Misfire, HELP?

ecm is jacked up, flash it

Re: Multiple Engine Misfire, HELP?

What does that mean and how do I do it?

Re: Multiple Engine Misfire, HELP?

you can try popping the battery cable loose for about 5 minutes. Then try flipping the key on and off I think 7 times. If that doesent work it will have to go into a shop. THe computers on the newer OBD2 jeeps are kinda picky

Re: Multiple Engine Misfire, HELP?

wolfpackjeeper said:

you can try popping the battery cable loose for about 5 minutes. Then try flipping the key on and off I think 7 times. If that doesent work it will have to go into a shop. THe computers on the newer OBD2 jeeps are kinda picky

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Doing this clears the check engine light correct?

We have one of those engine code readers that can clear the code, but whenever I clear the code it just comes back. It started out with the #3 cylinder misfiring but after the light came back on it showed two of them misfiring. So confusing:helpme:

Re: Multiple Engine Misfire, HELP?

the computer itself needs to reset. I dont rtemember if you can do it with the key on sequence or not. it may have to go to a shop. Find one near you with a genesis machine that can read all the stuff going on

Re: Multiple Engine Misfire, HELP?

Yeah, take it to a shop and say 'this dude on the internet said to reset my computer' and see how that goes.

If the code continues to come back up while the jeep is actually running poorly the computer is doing its job just fine and telling you there's a problem. Misfire codes are generated by the crank position sensor showing erratic rpm readings. Since it starts and runs fine, we know the cps is ok, and likely so is the wiring back to the computer. But you do have a rough run problem which can be caused by either engine mechanical issues, fuel, or spark issues. First step with a misfire, verify engine compression across all cylinders. If you have a weak hole, no amount of reflashing or sensor replacing is going to make it run better.

that genisis machine that I mentioned earlier, reads sensor values real time. find a tech that knows his stuff and he will be able to tell you if they are withing acceptable values. I know of two different people who have had to have computer work done on a 97 or newer XJ. One because of a similar problem as this, the other for an ac problem(computer was not turning on the compressor) and I know of several problems with the liberties involving this kind of thing.

There comes a point and time when it pays to have your truck hooked up to a realtime scanner(not that code reader at the parts store) And go from there, especially if you do not own a good compression tester or have never done the job before. There is only so much you can do with the internet

Exactly. That's my day job and a quick glance at the PIDs (as we call them in Ford-land) will tell you almost everything.