If you believe you might have a miss fire on one or more cylinders. Get a compression gauge and test it. Also is you're throttle body clean? air filter. maybe check your map sensor to. and cap and rotor and the wiring. Always remember an engine needs these to operate. air,fuel compression and spark. Their a guy I used watch on youtube. Who would work on a Jeep Grand Cherokee 1995 - 98 and they both have the same 5.2l That is if yours is that. But he goes into great details of fixing and making stuff run. Here he is.

 

Every electronic part on the throttle body has been changed.I just replaced the map sensor as well as plugs( Copper Champion) Did a full cap, wires and plugs just a little while back. Air cleaner is good and I did clean the throttle body again. I did but a new set of injectors from 1AAuto but one or more failed so OE ones were put back in. They gave me the run around because they failed after two months so they we no longer covered.Fuel pump and tank clean was done a few months back. The only thing I haven't done is a compression check but until this daily rain goes away, that wont happen soon. This truck sat for a few years over a transmission issue that has been solved through doing a rebuild. I have had this truck down to the intake doing a upgrade so a lot of the parts have been replaced. It's driving ok but you can feel the misfire lightly when you start it up. The idle is a little rough and you can barely see it on the rpm side needle. around 40 to 50 mph you can feel a slight misfire going on. I may take it at some point when cash is available have the injectors cleaned.

 

If you have a halfway decent scanner, have a look at the misfire counters, see which cylinder(s) are the issue.

 

I have a Zurich scanner from Harbor freight. I'm not sure if it will show what your asking?

 

If it's spark related you can put on a timing light on the wires (coil or cylinder) to see whats going on.

 

So far the misfire is minor. I mean you can feel it but rpm gauge barely moves. You can feel it a little more on cold start. As much as it's a pain to get to, I might go ahead in the coming couple of weeks replace cap, rotor and new wires. Seeing I did them during intake gasket change. I was thinking that was about a year ago. I really need to start writing things down. We are just getting rain everyday right now. I really need a break so I can do a oil change this weekend. It seems the lube shops around here don't do the 10/30 oil anymore. They do a 5/30 weight. This truck normally runs pretty smooth. As soon as I can do some test. I will update. Thx

 

Sorry, weather has been crappy lately along with high temps. I did get in the new sensor. It says it mopar part number 56027870 made in Germany. (crank sensor). I am still trying to figure out how to work this Zurich for live data. The idle issue is just plain weird. I drove it to work this morning and it seemed pretty smooth. Started it up leaving work and idle was again little rough but as normal rpm gauge barely shows it. You can feel it lightly misfire going down the road. I did buy a socket style allen wrench set for this round on changing sensor. It's just so darn tight getting a wrench in there with your hands. I also thinking about giving it new wires, cap and rotor since I replaced the plugs. I mean it wouldn't hurt to give it a tune up anyway. Gas millage has been good. I am going to post pictures of the plugs that were changed. They didn't look all that bad.






I would have to go back and check each box if your looking for which cylinder each plug came from. I labeled each one as they were removed.

 

How old are the cap and rotor?? WIres?? Sure won't hurt to change 'em if they are old.

 

Maybe 8months +. I did it back when I did the plenum upgrade. At this point doing a tune up isn't going to hurt and hopefully maybe it will cure this misfire? Maybe I can get a better idea of when the intake was done through a thread search?

 

Cap and rotor should last longer than that.... Still, won't hurt to change 'em. Brass terminal cap please.