Chugging engine

Tiny
MTNGRRL822
  • MEMBER
  • 2003 FORD ESCAPE
  • 3.0L
  • V6
  • 4WD
  • 190 MILES
My car starts to misfire or lose fuel when it gets up to about forty five mph. It chugs then recovers, over here over. Once it starts, it will then miss at any speed and at stop lights. If I put it into neutral, the chugging stops. Only seems to do it with a power load on the engine.

Originally there were check engine codes of three and six cylinder misfires. There are no check engine codes now.

So far I have replaced the fuel filter, spark plugs, tubes/springs and the fuel pump. The pressure at the Schrader valve tests at 50 lbs.

I would appreciate any advice and/or the next diagnostic steps.
Thanks
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Thursday, January 5th, 2017 AT 12:10 PM

8 Replies

Tiny
STEVE W.
  • EXPERT
You have 50 psi fuel pressure which is low for that engine, you should have between 55-65 psi.

It sounds like a bad fuel pressure regulator. On the 3.0 it could be on the end of the fuel rail or inside the tank on the pump module. If it is on the fuel rail connect the pressure gauge and pull the vacuum line off If the pressure does not change or there is fuel leaking into the hose, the regulator is bad.
If it is not on the fuel rail it is on the pump. It is possible that you have the wrong pump. If you installed one without a regulator when it should have one you will get a low reading.
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Friday, January 6th, 2017 AT 4:27 AM
Tiny
MTNGRRL822
  • MEMBER
Thank you Steve! This gives me the next steps to take which helps me a lot.
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Friday, January 6th, 2017 AT 3:13 PM
Tiny
MTNGRRL822
  • MEMBER
Hi Steve, I just double checked that the fuel pump is compatable with my car & that the assemble included a new pressure regulator. I bought a mid-Irange Autobest pump. I will talk with the company to see if they will swap units.
If we go on the assumption that the new fuel pump is working correctly, is there something else that can cause the low pressure?
Thanks.
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Friday, January 6th, 2017 AT 3:43 PM
Tiny
STEVE W.
  • EXPERT
The only two items that control fuel pressure are the pump and the regulator. Unless you have a fuel line leak (would be a sizable leak spraying gas) or the pump power connections are bad nothing else there.

These days I count myself lucky when the parts are correct and working, get quite a few that are trash right out of the box.
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Friday, January 6th, 2017 AT 5:10 PM
Tiny
MTNGRRL822
  • MEMBER
Thanks again, especially for the educational parts. I know the pump power conn. Is good. I have ordered a new pump & I'll check for any leaks. Process of elimination. Thank you.
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Friday, January 6th, 2017 AT 10:26 PM
Tiny
KEN
  • ADMIN
Please let us know what you find so it will help others.

Best, Ken
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Tuesday, January 10th, 2017 AT 11:35 AM
Tiny
MTNGRRL822
  • MEMBER
Hi, I ended up replacing the fuel pump again. It helped but didn't fix the issue. The next step was replacing the ignition coils. That took care of the majority of the chugging. I believe all that's left is to get a computer 'reset' on the coils.
Thanks for the help.
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Tuesday, January 31st, 2017 AT 7:05 PM
Tiny
STEVE W.
  • EXPERT
Sounds like you should have it taken care of. Between low fuel pressure and some bad coils you have eliminated 99% of the available problems.
Post back once you run it a bit.
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Tuesday, January 31st, 2017 AT 8:12 PM

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