Need some help with EVAP system, misfiring, and P0455. | Ford Explorer Forums - Serious Explorations

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Need some help with EVAP system, misfiring, and P0455.


New Member
April 18, 2014
Reaction score
City, State
Detroit Metro Area, Michigan
Year, Model & Trim Level
1997 Explorer XLT 5.0LV8
Hey guys my name is Sean. I'm new here, not sure if this is the right area to post this, if it's not, I apologize, someone please direct me.

Ok here's the short rundown. Bought a 97 Explorer XLT 5.0L V8, 115k, known exhaust leak. (I could hear it on the test drive.) Everything else seemed in order, immaculate inside, few rust spots, but that's expected as I live in Michigan. Got it for $1800. Guy's mom has cancer, selling it to pay her bills. Replaced rear brake pads, they were crumbling because it sat so long without driving. Also replaced front left axle seal and topped off the differential fluid. (Both of these done at a shop.) The other day I was driving on the freeway, and over 65 mph it became very rough and started vibrating. Check engine light came on. As long as I was under 65 it was good. Then it started misfiring I guess, felt like I was pressing the gas, sometimes it would accelerate, sometimes it would delay. Took it to Autozone, ran the diagnostic, got the code. Took off my EVAP system, carb cleaned the purge valve and purge solenoid, check for cracks or leaks on the unit and the hoses, nothing I could see with the naked eye. Connected the hoses back. Disconnected battery, cleared the code. Was good yesterday, and now on my way back from work it's doing it again, maybe not quite as bad, but definitely noticeable. The only other thing is maybe a vacuum leak or my O-rings, so I've read with everyone who got that code. But I haven't found anyone with the misfiring/delay of acceleration problem. And now that it started back up again, it hasn't thrown me another code. So I'm thinking maybe I fixed my EVAP system blockage, and this is another problem? Why isn't my check engine light coming on when there's clearly something going on? It only has 115k miles, it can't be the trans already slipping...can it? Please tell me it's not the trans.

It was pretty dirty when I bought it, faded around the door trim and back trim. I painted that all black, blacked out the grill by sanding it and peeling the chrome off from a sticky I read on THIS SITE, and putting mesh I painted white behind it. It looks pretty good I think. Also blacked out the tailights and added some interior lighting. It looks great on the inside and outside, but under the hood, there's obviously something wrong.

Anyone with similar experiences or opinions, I would GREATLY appreciate it. I don't have the money to take it to a shop, and I'm not the best with cars, but if I have something to start from, I'm pretty confident I can do it, unless it's something huge. If you have any questions or need more info, or would like pictures, let me know. Thanks!

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Well start with the basics, when im looking at a problem like this I always bust out the fuel pressure tester. At higher speeds a dying fuel pump will exhibit exactly what youre talking about. It simply can't catch up with the load since its worn. Does the symptoms go away once you decelerate?

An evap leak wont cause poor running like what youre saying. It is for more an emissions standpoint.

Anyways, start with fuel pressure and let us know.

There is a large vacuum line that is on the drivers side ,front of the upper intake, its hooked to a steel line with a plastic squeeze connector and the other end is hooked to a thing under the battery, I have had a few of these split open on the back side, so at a glance they look fine, it causes exactly what you have, find it run your hand down it, see if that's it,

Its the main vacuum for the evap system,

Me and my cousin are searching, could you post a pic and show it to me? I'm sorry man, I'm so new to this.:(

To the left of the rusty circle kinda in the middle of the pic , the black thing with the dirty white triangle, that's the connector follow that hose and feel it to see if its cracked


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It might not be your problem but its a common problem that causes your issues and its easy to check

Found it. It says Gas/Fuel line on mine. The rubber on it feels dry rotted. Called O'Reilley's. Going to go get one right now. Thanks for the help, I'll let you know what happens!

Hows it going

A cracked fuel filler hose and faulty fuel cap can also
trigger the P0455 code (Gross EVAP leak).

I just picked up the hose from Auto Zone, waiting for the truck to cool down. Can I just cut off the old EVAP vacuum line?

Just replaced the house took a little test drive. Seems ok, ill have to see if the code pops back up or the symptoms start again. Idk I feel like that was way too easy lol.

Let us know

So far so good. We'll see how she drives the next few days and if it tbrows me another code. Thanks so much for your help guys, especially 'delexploder'. It was very much appreciated!

Glad to here so far so good! If that changes let us know,

Ahh still doing it. Haven't had a chance to come on here and tell you guys, been busy at work. I see a few cracks in the fuel cap housing, the white thing the fuel cap screws into. Is that bad? I mean it can't be good lol. What's that post called? My fuel line looks like it could be replaced too.