Colin Eaton

I have a 2000 jeep xj with 170k on it and on start up it will randomly misfire. Like randomly sometimes on start up it'll be fine and others it'll misfire until I give it some throttle. I pulled coeds P0300 P0301 and P0302. Also after giving it some throttle there's a strong smell of gas. I Just changed the spark plugs this summer, replaced cam and crank sensor. The only thing I can thing is that my coil pack is starting to go or the computer might be. Any help would be great it is a woods rig so it's seen some water but not enough to do damage.

tjwalker

You have two issues which likely are not related.

1. Use your nose and isolate the source of that gasoline leak. Even the smallest of gas leaks can create a big smell. Know that a small gas leak can lead to a fire.

2. As for the misfires, as it is multiple cylinders and also the "random misfire" code, I'd first look for a common root cause. The #1 thing to verify is fuel pressure. Must be done with a fuel pressure gauge which can be rented from many parts stores, call around for availability. The fuel pressure spec. for the 2000 is 49 psi, plus or minus 5 psi. Testing your "MAP SENSOR" would also be a good idea as it is involved in fuel/air ratio.

Colin Eaton

the only reason think the two are connected is because the smell only occurs when the jeep misfires almost as if it's running rich. Also the more I'm thinking about it could my coil pack just be going bad because I can't recreate the situation on it misfiring like I said sometimes it starts fine and others it just misfires, it kinda chooses when to do it.

5-Speed

Test it and find out if its going bad

PatHenry

I don't get the logic of gas smell corresponding to misfire-type behavior pointing to a bad coil pack. Please elaborate.
Logically I'd be thinking you have a leak in the fuel line somewhere that's causing it to periodically dip in pressure (resulting in misfire-type behavior), but I'm not an expert.

Colin Eaton

If the coils are bad and not causing spark then its dumping fuel strait through the cylinder. Causing the rich burn smell

Colin Eaton

I just want some confirmation that I'm going down the right path because right now the jeep is parked an hour away from me and I only get to work on it on Saturdays because of school and work. I'll test it using the chart to see. The only reason I think it's not a fuel leak is because even with it sitting I'm getting no fuel puddles and it's not constant like i could drive it a week and it'd maybe misfire once or twice and it's not consistent. Like if it is a fuel leak wouldn't it be more consistent. I'm sorry I'm not trying to say you're wrong I'm kinda new to troubleshooting engine's and I'm just curious if a fuel leak would be more consistent then random. Also i probably should have been more clear but it can be like I shut it off start it back up and boom misfire or even cold starting it misfires. Like I said it's completely random

GigoloSoldier

I am having this exact same issue. Was a solution ever found?

It only happens on startup and it sounds like something in the serpentine system is dragging.

Thanks

Colin Eaton

No I never found what caused it. A few weeks after it crashed in the woods and it took a few months to fix so it sat for a few months and once it went back on the road it never did it again. My best guess was I cracked the head since it has the 0331 head on it and it loved to overheat within minutes after I fixed all the body damage but unfortunately I don’t know the complete reason.