can an emission leak cause a idle issue?

[Blackout51]

ive been dealing with a high idle on my 1998 4.0 sohc and cannot figure out the cause, I reset everything last night and while driving it today I got two codes, the code saying the iacv can't reduce the idle (I forget the code number) and the p0455 code, which is a gross evap emission leak, the cause of this code I believe is a bad fuel filler neck because when I fill the tank all the way up fuel shoots out from under the backside of the filler hole, like it drains out under the car not out of the fuel filler door, but my question is could this leak cause a high idle? and I know the high idle isn't because of a vacuum leak because I checked all of the hoses and im not getting a lean or rich code either

 

[Anime]

You should probably post this in the 1995-2001 forum for better responses from those with the same vehicle and engine.

Emissions issues/emission leaks can definitely cause idle problems. I'd guess it's more air/intake/exhaust related than with the fuel filler neck, but even something as simple as a loose/missing fuel filler cap can throw an emissions code, so sure, a leak that's spouting fuel will probably trigger that as well.

Note that filling up a fuel tank all the way, as in topping it off so the tank is completely full and/or fuel goes all the way to the top of the filler neck is a bad idea and can be the cause of stuff like this. The fuel tank is only designed to be about 90-95% full, with air space at the top to allow venting and allow expansion since you're usually putting in cool fuel from an in-ground tank into a fuel tank in a warm/hot environment.

Best bet when filling up all the way is to stop filling up when the nozzle clicks. Anything after that and you are asking for problems.

After you fix the leak, I'd say inspect the intake gaskets or look for an intake/exhaust leak anywhere from the filter box, intake tube, intake manifold, exhaust manifold, converter, O2 sensors, muffler, or try another IAC valve.

 

[Blackout51]

You should probably post this in the 1995-2001 forum for better responses from those with the same vehicle and engine.

Emissions issues/emission leaks can definitely cause idle problems. I'd guess it's more air/intake/exhaust related than with the fuel filler neck, but even something as simple as a loose/missing fuel filler cap can throw an emissions code, so sure, a leak that's spouting fuel will probably trigger that as well.

Note that filling up a fuel tank all the way, as in topping it off so the tank is completely full and/or fuel goes all the way to the top of the filler neck is a bad idea and can be the cause of stuff like this. The fuel tank is only designed to be about 90-95% full, with air space at the top to allow venting and allow expansion since you're usually putting in cool fuel from an in-ground tank into a fuel tank in a warm/hot environment.

Best bet when filling up all the way is to stop filling up when the nozzle clicks. Anything after that and you are asking for problems.

After you fix the leak, I'd say inspect the intake gaskets or look for an intake/exhaust leak anywhere from the filter box, intake tube, intake manifold, exhaust manifold, converter, O2 sensors, muffler, or try another IAC valve.

Oops yeah I did click the wrong area to post in, but when I filled it up it start sorting the gas out then it clicked off, I try not to keep filling it after it clicks off which is another thing that confused me because I've never seen it shoot out then click off