My 2004 wrangler runs rough and stalls. sometimes the engine light comes on, sometimes it just bucks. I stop and start it right up. the ignition module has been replaced

sounds like your fuel pump is dying.

does ur car have a engine light come on? cant really tell u answer if u dont explain more.

Try replacing Co2 sensor, most people don't realized that unit need replacing every 50-75k miles also. if that does not work, take it to the dealer and have them plug it into the computer, that will allow for them to narrow it down. with service engine light on, it will effect some of your gas mileage and the performances. The dealer charge somewhere around 50 bucks to diagnose using their computer, however 50 bucks will appilied toward the repair bill if they do the work.

Have you checked the firing order to make sure the plug wires are in correct order. Sometimes an engine will run but rough if 2 wires are mixed but it could be that there's more than 2 mixed up.

Injectors, even if one is bad, the increase in resistance in the SFI system kills the other injectors too. When it starts to run bad, unplug injectors one at a time to see if it runs better.

sounds like a ignition problem, try new cap rotor and wires and plugs if this does not fix your problem it is either your coil or distribitor

I had the same exact problem on my 2004 Colorado (3.5L). Cleaned the MAF sensor (with MAF sensor cleaner) and throttle body/plate - cleared it right up.

the 1st thing to do is go to any Kragen or Autozone parts store and have them run a trouble code test for the reason the light is on, it is free, then post that code back here.

Go to Advance or Auto Zone and have them run an obd scan on it and it will pin point why your light is on and could solve your problem. This is often done for free.

I can almost guarantee its the ignition coils. Its common with the 2004 mazda mpv. They are very expensive but I just changed my #3 coil and boy im I glad I did that. With the Mazada mpv 2004 hopefully a check engine light will come on so you can see which ignition coil it is. Once you find out change it and the spark plug that goes under it. If its one of the back ignition coils its gonna be expensive or time comsuming. I would change all three coils in the back and all three Spark plugs so that you dont have to worry about them again since you have to open the manifold just to get to them. I recomend taking it to a auto shop that you trust. While your back their you can change the pvc valve and bromet I think its called (the cushion for the pvc valve). Its all in the same area. The ignition coil could run from about 45 dollars each to about 65 depending on where you go. One more thing, if the check engine light comes on you have to check it quick because it cancells it self out if the ignition coild is not that bad yet. the sometimes it stalls and sometimes it doesnt syndrome. you take it to the shop and it doesnt happen again until your home thing lol. Thats just the beggining of it going bad.

After I changed my Iginition coil and all three spark plugs in the back of the engine the car runs like a race horce. no more stalling. im very happy I did that. It cost me about 125 for the coil and the three spark plugs and a new thermometer for another issue. and about 200 bucks to put them in, I think I got a good deal considering most dealers in nyc charge 100 bucks an hour to work on your car. Its not that big a deal of the work. You just have to know what your doing. It took him about 5 hours to complete the job. I hope this was helpful.