Misfiring/idling weird

[shoftw]

I've been having a hard time trying to figure out why my 95 Sho is misfiring at high rpm also why it starts up funny like it isn't getting enough fuel.

 

[SHOdded]

Checked fuel pressure? Any fuel in the vacuum line to the regulator? And of course, codes.

 

[rubydist]

start with the codes.

how old is the fuel pump?

 

[luigisho]

Codes and in addition to fuel delivery check the plugs and wires to make sure spark path is good

 

[shoftw]

start with the codes.

how old is the fuel pump?

No codes at all

 

[shoftw]

Codes and in addition to fuel delivery check the plugs and wires to make sure spark path is good

Replaced

Checked fuel pressure? Any fuel in the vacuum line to the regulator? And of course, codes.

Checked fuel pressure? Any fuel in the vacuum line to the regulator? And of course, codes.

After i turn it off the pressure goes down fast and no fuel in the vacuum line

 

[luigisho]

Might be a bad check valve letting the fuel pressure drop too soon or a reg going bad. Did you check fuel pressure with a gauge at the schrader valve?

 

[shoftw]

Might be a bad check valve letting the fuel pressure drop too soon or a reg going bad. Did you check fuel pressure with a gauge at the schrader valve?

It's normal at idle I'm gunna check it when I turn it on see if what the pressure is

 

[shoftw]

Might be a bad check valve letting the fuel pressure drop too soon or a reg going bad. Did you check fuel pressure with a gauge at the schrader valve?

It starts up fine but after a few times of starting up it starts to act like it doesn't have enough fuel

 

[shoftw]

Might be a bad check valve letting the fuel pressure drop too soon or a reg going bad. Did you check fuel pressure with a gauge at the schrader valve?

Also it misfires at high rpm

 

[rubydist]

so if there are no codes, then the likely candidates are 1) a sick fuel pump or 2) a bad fuel pressure regulator.

 

[luigisho]

so if there are no codes, then the likely candidates are 1) a sick fuel pump or 2) a bad fuel pressure regulator.

That is my first best guess as well. I think I would look at fuel pump first as they fail more often.

You can get misfires and hesitation from other malfunctioning sensors that effect proper ignition of fuel such as MAF or something that influences air/fuel metering for ignition

 

[shoftw]

so if there are no codes, then the likely candidates are 1) a sick fuel pump or 2) a bad fuel pressure regulator.

The auto parts said no codes I'm gunna do the key on and how do you clear the system because I took off a lot of things to figure out the problem those codes are stored I need to clear it then do it

 

[rubydist]

here:
http://www.troublecodes.net/ford/

 

[SHOdded]

http://web.archive.org/web/20090917070939/http://www.shophoenixproject.com:80/eec/eec.htm

 

[shoftw]

here:
http://www.troublecodes.net/ford/

What's to the fuel pressure past 4,000 rpm?


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[luigisho]

I'm just spitballing as I don't have the figures at hand but I think under load you're probably looking between 35-40. Also is this a manual or automatic car? Is the high rev miss tested in park or driving on the road? There is a rev limiter that kicks in on automatic cars in park

 

[shoftw]

I'm just spitballing as I don't have the figures at hand but I think under load you're probably looking between 35-40. Also is this a manual or automatic car? Is the high rev miss tested in park or driving on the road? There is a rev limiter that kicks in on automatic cars in park[/QUOT
Manual


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[luigisho]

If it was my car I would replace the fuel pump (and maybe the sending unit at this age) and go from there. Maybe an experienced tech has more tests to help narrow it down even more, but you will probably pay more for that than replacing the high probability failure part. The other parts to consider is maybe a failing relay module to the fuel pump, PCM, clogged fuel filter, faulty injector. Not much left in the fuel delivery system other than lines and regulator