Came outside and noticed something was hanging down, got closer and realized it was the tailpipe. Rusty and broke right off. Figure I'll worry about it later. Four days later, the check engine light comes on for the first time since I've owned it (only a couple months) and find out it's the P0455 for an "Evap Emission System Leak Detected") and of course the guy at auto zone says "it's probably just yer gas cap is loose!" and so I read a couple threads on here of people with the code too and I don't think it's the cap, I put it on tight every time and I went ahead and got more gas and made sure it was on tight and the CEL is still on. Is it possible these two occurrences are related or is it just a coincidence? Pic attached of tail pipe hanging down. Also, another issue I've been having that may be related, sometimes on startup (never on a cold start though) it'll shake and rattle like crazy and will eventually go away after a min or so. Of the few times it's done it, I've tried different things to try to understand it more: one time I put it in drive and tried to drive with it rattling and gave it gas and it wouldn't really go, it just kept rattling and the gas wouldn't do much and then after a few seconds it finally went. Another time I really gunned it to try to make it go and then it stalled out, had to turn it back on and then it went just fine. Another time I just turned it off and back on and no rattle. Happens with ac on and with ac off, no difference. Engine temp is normal, oil pressure normal. Let me know if there's anything else to add to understand this. Thanks in advance guys

 

P0455 is a large leak detected. If it isn't the cap not sealing, I would inspect the lines from the tank going forward and at the the canister under the hood. Posting what year would help too.

 

Is there anyway the system can be sucking in the exhaust fumes under the jeep and thats whats causing it?

 

No.. The system is self checked by vacuum...If it doesn't hold vacuum it trips the code...If I had to tie the two together I'd say the tailpipe rotted off, and either took the line with it on the way down or bounced off the ground hitting one of the EVAP lines..As already stated get under there and check the lines..If you've got enough rust to drop the exhaust pipe I'm betting the steel lines are rusty too.. Could be any number of causes..

 

More likely it's pure coincidence. There are two things to remember about coincidence:

1. Never assume its coincidence.
2. Never assume it's not.

 

But isn't the lines line along the drivers side and the tail pipe is on the passenger side? I would start tracing the evap lines from tank up to the front. Mine was rusted out between the tank and canister
.

 

Yes, you're correct...I was just looking at how far back it rotted off and it's back there between the tank and leafspring.. My first look I thought it was the next one forward with more swinging in the wind.. In any case, check the metal lines and the rubber.. It's a relatively simple system and the vacuum leak could be anywhere..

 

Ok. Will do. And it's a 2000.

Interesting. It's probably hard to tell from the pic, I'll take another tomorrow when it's light outside but where it rotted off is very far toward the back, it's just right there at the end. I'll have to check the lines though too didn't think of that.

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LOL.

Ok will keep that in mind as well and check for that in the morning. NOW, interesting development. I think I may have found out what the heck was going on with the rough idle misfiring warm start stuff. Heat sink/vapor lock! Finally found out that that is a thing. Didn't even know that could happen. Well, I just bought the first thing I could get my hands on that seemed like it would help: spark plug heat shield covers. There was two in a pack so I cut them into thirds to make six and I cut a slit down them all so I could fit them over all of the fuel injectors and then zip tied them around each. Just a bandaid for now but at least it might help for a bit until I can get a heat shield kit of some sort or upgrade the injectors and also I probably need a new thermostat. Just Empty Every Pocket amirite!? Nah, I love the Jeep. I'm glad we traded the horrible Rio in for it. Now I just need to get my Ranger..