PO455 Code and Missing Upon hard Acceleration

I have a '00 XJ. Recently, my engine light has come on a few times after fill-up. I've read the other posts regarding this, but none included this: when I accelerate, as it's coming up in the RPMs, it "bucks" or misses a few times. I was wondering if having a leak in the fuel/emissions system somewhere (which is throwing the code, no doubt) is allowing air into the fuel lines running from the tank to the front which is, then, causing the jeep to miss.

I've checked for leaks in the three hoses coming off the rear box, all the places where there are connection hoses, and where the two lines attach in the engine compartment. I've also replaced the gas cap. I can deal with the engine light, but not the bucking/missing.

Any thoughts?

Sent you a PM.

Your problems MAY NOT be related, however a large leak in the EVAP system could be screwing up your fuel mixture, so fixing that problem is your first step.

steveybass said:

I have a '00 XJ. Recently, my engine light has come on a few times after fill-up.

Any thoughts?

Click to expand...

Start by pulling the engine codes and see what it thinks is the problem.

Here is a link to a good article on "evaporative emission system leaks", which is what you have (P0455 is a gross leak).

There are a number of possibilities. I would start by inspecting every piece of the evap systems tubes/hoses looking for that leak. Vacuum hoses (they can crack with age) are not an uncommon cause.

http://autorepair.about.com/library/faqs/bl010h.htm