Misfire at idle 300 i6 f150

[Orangepeel]

The regulator actually keeps the pressure from going too high, so if it's not leaking , it's ok. . That's why the pressure should increase by disconnecting the regulator's vacuum. You can check for a weak pump by disconnecting the regulator's vacuum and monitor the fuel pressure as you goose the throttle. If the pressure drops a lot (10 psi or greater) then springs back up, the associated pump is weak.

I go by what my factory manuals state. For 1987-1994 300's the idle pressure should be 45-60. On 1995-1996 the pressure should be 30-45 psi at idle. 1996 was the last year that beast engine was made.

You have a lean miss as indicated by your highly positive long term fuel trims. Don't pay much attention to the short term trims.The computer is adding a lot of additional fuel to maintain proper air/fuel mix. Low fuel pressure, stuck EGR, exhaust leaks upstream from O2 sensor, major vacuum leaks or bad data from a sensor.

Both are from direct hit which do you trust? Hard to verify and properly check things when the information isn’t even confidence inspiring.

 

[Joba27n]

Both are from direct hit which do you trust? Hard to verify and properly check things when the information isn’t even confidence inspiring.

This source has served me well since I left the dealer

 

[Lubener]

Both are from direct hit which do you trust? Hard to verify and properly check things when the information isn’t even confidence inspiring.

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View attachment 295663

You are making a mountain out of a mole hill. My source is the Ford factory service manual. You can't get any more reliable information than that.

You don't pay attention. Your first screen shot is for 1995-1996 engines which applies to yours. The second screen shot applies to 1987-1994 engines which utilized a higher fuel pressure and different injectors..

 

[Orangepeel]

You are making a mountain out of a mole hill. My source is the Ford factory service manual. You can't get any more reliable information than that.

You don't pay attention. Your first screen shot is for 1995-1996 engines which applies to yours. The second screen shot applies to 1987-1994 engines which utilized a higher fuel pressure and different injectors..

Your dead ass wrong! Both are from the same vehicle with vin number inserted in the search. Have you ever used direct hit?
Direct hit identifix is where this info is from with the vehicle by vin inserted just because it doesn’t match your assumptions of what is accurate doesn’t mean i am not paying attention.

 

[Orangepeel]

You are making a mountain out of a mole hill. My source is the Ford factory service manual. You can't get any more reliable information than that.

You don't pay attention. Your first screen shot is for 1995-1996 engines which applies to yours. The second screen shot applies to 1987-1994 engines which utilized a higher fuel pressure and different injectors..

Fuel injectors show compatibility between years and this is the fuel pressure from ford per identifix. Also please explain how needing to know the proper fuel
Pressure is making a mountain out of a mole hill? A difference of 20psi is definitely going to make a difference. It is imperative to have the right information when performing diagnostic testing.

 

[Orangepeel]

This source has served me well since I left the dealer

They have the same specs as identifix that’s a little more reassuring.

 

[Lubener]

Your dead ass wrong! Both are from the same vehicle with vin number inserted in the search. Have you ever used direct hit?
Direct hit identifix is where this info is from with the vehicle by vin inserted just because it doesn’t match your assumptions of what is accurate doesn’t mean i am not paying attention.

I suggest you take your truck to a competent technician and get it fixed.. You are just spinning your wheels and not getting anywhere.

 

[Orangepeel]

I suggest you take your truck to a competent technician and get it fixed.. You are just spinning your wheels and not getting anywhere.

Would you like to pay for that? The fuel pressure is low on both tanks so next step is a fuel pressure regulator. You’ve made sweeping comments that are wrong and then get pissy when someone shows your wrong. Typical of today’s day and age!

 

[Orangepeel]

Once the fuel pressure regulator is replaced I’ll
report back.

 

[ripcord]

You mentioned earlier that the fuel pressure didn't rise when you disconnected the vacuum line from the regulator. This usually indicates a weak fuel pump.

I would try to verify fuel pump voltage. Also test the max fuel pump dead head pressure. It should be higher than the book pressure or you have weak pumps.