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Ask AMEDEE Your Own Question
Category: Ford
Satisfied Customers: 26041
Experience:  ASE CERTIFIED TECHNICIAN ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
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High rpm stumble at 3000 rpm or more. Fuel pressure is ok at

Customer Question

high rpm stumble at 3000 rpm or more. Fuel pressure is ok at 65 lbs. do I have a intake vacuum leak? Idles fine.
JA: Where exactly is the source of the leak? Could you take a picture of it if asked?
Customer: no. I can"t tell for sure. Squirted soapy water all around but could not see anything. I'm guessing at this point.
JA: What is the model of your '65 Ford?
Customer: 2003 explore sport trac 4.0 sohc.
JA: Are you fixing your vehicle yourself? What have you tried so far?
Customer: Yes. Checked fuel pressure with guage and all is fine . car ran fine yesterday, then wouldn't start two hours later .Cranked but wouldn't fire up. today it starts,idles smooth but lopes at 3000 rpm??????
JA: Anything else you want the mechanic to know before I connect you?
Customer: no.
Submitted: 9 months ago.
Category: Ford
Expert:  AMEDEE replied 9 months ago.

Hello and welcome!

My name isCustomerand I can assist you with your question.

Expert:  AMEDEE replied 9 months ago.

Is the check engine light on?

Are there any codes in the computer?

Are you looking for possible causes?

Customer: replied 9 months ago.
No CEL. No codes. Yes I'm looking for cause/causes to check.
Customer: replied 9 months ago.
okay . Where are you???
Expert:  AMEDEE replied 9 months ago.

Sure thing, I will be happy to help.

Expert:  AMEDEE replied 9 months ago.

The most common cause of this condition is plugged exhaust or a bad mass air flow sensor.

Plugged exhaust will restrict air flow through the engine which will cause this surging your talking about.

A faulty mass air flow sensor can and will result in a severe lean condition under a load.

Expert:  AMEDEE replied 9 months ago.


I see you have viewed my last reply but have not responded back. I am just checking in to see if you have any further questions or to see if you still need help with anything? If so, please let me know as I will be happy to help. If I have answered all of your questions, please dont forget to honor the good faith rating system to complete this conversation.

Thank you and have a great day!