Ford

Have Ford questions? Ask a mechanic for answers ASAP

Ask an Expert,
Get an Answer ASAP!

Hard start, when it starts RPMs jump up and down and

Customer Question
Hard start, when it...

Hard start, when it starts RPMs jump up and down and gradually decrease until it shuts off. During this time i press the gas but it doesnt even seem like the gas is pumping when I press the peddle. I do hear the pump prime before start. The PCM has been changed twice. The fuel pump has be changed. The truck will run continuously after a couple of tries but it is a rough idle

Mechanic's Assistant: Is the rough idle intermittent or consistent?

Consistent I thought it might be the enertia switch but not sure

Mechanic's Assistant: What is the model/year of your Ford?

2001 f150 4.2 liter v6

Mechanic's Assistant: Are you fixing your F150 yourself? What have you tried so far?

Fuel pump, fuel filter, EGR throttle body sensor, air temp. sensor, mass air flow sensor, EGR vacuum solenoid, had exhaust system checked and was said to be fine.

Mechanic's Assistant: Anything else you want the mechanic to know before I connect you?

Thats it

Submitted: 6 months ago.Category: Ford
Show More
Show Less
Ask Your Own Ford Question
Answered in 5 minutes by:
3/23/2018
Ford Mechanic: AMEDEE, FORD TECHNICIAN replied 6 months ago
AMEDEE
AMEDEE, FORD TECHNICIAN
Category: Ford
Satisfied Customers: 28,500
Experience: ASE CERTIFIED TECHNICIAN ADVANCED LEVEL SPECIALIST. Wisconsin certified emissions state inspector
Verified

Hello and welcome!

Thank you for your question. My name isCustomerand I will be happy to assist you today. I am reviewing the details now.

Ask Your Own Ford Question
Ford Mechanic: AMEDEE, FORD TECHNICIAN replied 6 months ago

Is the check engine light on?

Are there any codes in the computer?

Are you looking for some possible causes?

How long ago was the fuel pump replaced?

Ask Your Own Ford Question
Customer reply replied 6 months ago
No Check engine light on.
air flow readings a all over the place and the fuel flow reading is all over the place.
Looking to fix it, tired of throwing parts at it. Already spent $5,000 at ford and they concluded it was my cool air intake thats been on for 10 years and has never given me problems before.
The fuel pump was replaced 2 months ago and was running good until I had ford look at it and they replaced the PCM, sychonizer, spark plus, fuel relay, then rewired the fuel relay, coil and plug wires.
Ford Mechanic: AMEDEE, FORD TECHNICIAN replied 6 months ago

Thank you for that information. Are you sure the fuel pressure regulator is not leaking fuel into the vacuum hose/line?

What is the fuel pressure at when this happens?

Ask Your Own Ford Question
Customer reply replied 6 months ago
I do not have a gauge to check it. I
Ford Mechanic: AMEDEE, FORD TECHNICIAN replied 6 months ago

Ok, well, you will need to get one and check it to diagnose it correctly if you don't want to throw parts at it. That is your next step.

Also, dont forget to check the fuel pressure regulator.

Ask Your Own Ford Question
Customer reply replied 6 months ago
roger. I will have that checked.
Ford Mechanic: AMEDEE, FORD TECHNICIAN replied 6 months ago

Sounds good, let me know

Ask Your Own Ford Question
Customer reply replied 6 months ago
will do. thanks a bunch.
Ford Mechanic: AMEDEE, FORD TECHNICIAN replied 6 months ago

You bet!

Ask Your Own Ford Question
Was this answer helpful?

How JustAnswer works

step-image
Describe your issueThe assistant will guide you
step-image
Chat 1:1 with a ford mechanicLicensed Experts are available 24/7
step-image
100% satisfaction guaranteeGet all the answers you need
Ask Ron Your Own Question
Ron
Ron
Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 25,022
25,022 Satisfied Customers
Experience: 23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs

Ron is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

AlvinC answered a question about my Ford truck that only someone with an in-depth knowledge of his subject would have known what was going on.

Rich DUSA

Because of your expertise, you armed me with enough ammunition to win the battle with the dealer. They are installing a fuel filter and fuel pump at no charge to me.

MollyUSA

I needed help with my car on Saturday morning....got a response in 5 minutes, and it was the perfect solution. Thanks again to your service.

Jason V.Kirkland, WA

I do know, after going though this with JustAnswer, that I can somewhat trust my mechanic but I will always contact you prior to going there.

BRNew Jersey

I would (and have) recommend your site to others I was quite satisfied with the quality of the information received, the professional with whom I interacted, and the quick response time. Thanks, and be sure that I'll be back whenever I need a question answered in a hurry.

Stephanie PElm City, NC

used your service this weekend with "Trecers" help. thank you ,thank you, thank you. replaced an A/C fan motor. Local Auto Zone had part. $15.00 "tracer" fee and $40.00 for parts, I saved several hundreds of dollers at a shop. i will recommend you and use you in the future.

David L.Richmond, TX

9 dollars, 2 hours of my time, and I drove away. Your diagnosis was right on the mark. Thank you so much.

PhilMarysville, CA

< Previous | Next >

Meet the Experts:

Ron

Ron

ASE Certified Technician

25,022 satisfied customers

23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs

Chris (aka- Moose)

Chris (aka- Moose)

Technician

29,223 satisfied customers

16 years experience

John Mc

John Mc

Ford Technician

5,495 satisfied customers

19 years Ford Lincoln Mercury experience

Chuck

Chuck

ASE Certified Technician

1,685 satisfied customers

33 Years Experience,Ford Senior Master,ASE Master,L1 Advanced Engine Performance

Cam

Cam

Journeyman Automotive Technician

10 satisfied customers

GM Grand Master Technician 2007. 14 years Automotive experience.

Mike V.

Mike V.

Auto Service Technician

1,591 satisfied customers

25 years experience on all makes and models, Licensed NYS Inspector.

Richard

Richard

ASE Certified Technician

1,524 satisfied customers

12 years at a Ford Lincoln/Mercury and Jaguar dealer as a technician and shop foreman.

< Previous | Next >

Related Ford Questions
04 f150 sputters and dies when pressing gas pedal from idle.
39;04 f150 sputters and dies when pressing gas pedal from idle. … read more
Jaybird61
Jaybird61
Master Automotive Mechanic
2,334 satisfied customers
I have a 2002 f150, 6 cylinder 4.2 lean bank 1 & 2. My
I have a 2002 f150, 6 cylinder 4.2 lean bank 1 & 2. My mechanic changed the gaskets, the sensors, the gas filter, clean everything he could think of. But code stays the same. what is he missing? … read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
29,223 satisfied customers
I have a 2008 Ford F-150 4.2 liter replaced maf map plugs
I have a 2008 Ford F-150 4.2 liter replaced maf map plugs and fuel pump vehicle dies when u plug I'm mass air flow sensor … read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
29,223 satisfied customers
I have a 2000 Taurus with a 3.0L v6. Recently it has begun
Hello, I have a 2000 Taurus with a 3.0L v6. Recently it has begun to stall intermittently. The first two times happened at stop lights. I was at a dead stop and the engine spontaneously shut off and g… read more
HDGENE
HDGENE
Master Technician/Lead Technician
Associate Degree
2,835 satisfied customers
Ford f-150: I have an 07 f150 with a 4.2. It idles rough on
I have an 07 f150 with a 4.2. It idles rough on warm start up. It has new plugs and wires. Firestone told me they cleaned the throttle body. It also missed a couple times yesterday as I was waiting to… read more
cloe0626
cloe0626
800 satisfied customers
i have a 1998 f150 with a 5.4 liter engine. it has no power
i have a 1998 f150 with a 5.4 liter engine. it has no power and when you take from a stop light it jerks or shakes. i changed the coils about a month ago for multiple misfires but its not setting any … read more
James
James
Bachelors degree automotive technology with minor in diesel
3,578 satisfied customers
F150: 2006 F150 4.2 V6 The truck starts and idles, once you
2006 F150 4.2 V6 The truck starts and idles, once you give it gas it stumbles. If you put it in gear runs rough. The truck can barley be driven so it sits!! We have replaced the plugs, wires, & coil a… read more
Kenny Z
Kenny Z
Ford Senior Master Technician
High School or GED
16 satisfied customers
ford f150 4.2 liter v6: i have a 1999 ford f150 xlt 4.2 liter
i have a 1999 ford f150 xlt 4.2 liter v6 engine. I have also had the error codes for lean bank 1 and bank 2. but my situation has gotten more dire. now after my truck warms up to operating temps it st… read more
James
James
Bachelors degree automotive technology with minor in diesel
3,578 satisfied customers
2001 f150: v6..air filter..egrand bought a new egr position sensor
I have 2001 f150 4.2 v6. If I drive it for 15-20 mins then shut it off to run into a store or gas station say 10 or 15 mins when I go to restart the truck to head home it will stall.This happens when … read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
29,223 satisfied customers
97 ford f-150: injector..crank sensor..coil..I tried the 99 pcm
I have a 97 ford f-150 with a 4.2 engine I put A late model 99 engine in and the injector plugs had to b changed in order to plug them in Also the crank sensor was at the bottom of the crank pulley on… read more
AMEDEE
AMEDEE
FORD TECHNICIAN
28,500 satisfied customers
I have a 1999 e-250 4.2. it back fires, slow acceleration.
i have a 1999 e-250 4.2. it back fires, slow acceleration. i changed the spark plugs, maf sensor, o2 sensors and the egr. im lost from here. can you please help.… read more
davehop
davehop
Diagnostic Technician
Ford Master Certified Technician
1,171 satisfied customers
2000 f150: 4.2 v6 it starts and idels..accelerate without breaking
truck is a 2000 f150 with a 4.2 v6 it starts and idels but will not accelerate without breaking up?… read more
Tim West
Tim West
Service Manager
Computer/ Automotive certifications
16 satisfied customers
F150: v6..EGR diff pressure sensor..fuel pressure..injectors
hello im working on a 03 f150 w/v6 4.2 i am geting a p0171 & p0174 codes. i have checked or changed the following: mass air flow, EGR cleaned, EGR diff pressure sensor, pcv valve, checked vaccume and … read more
Tim West
Tim West
Service Manager
Computer/ Automotive certifications
16 satisfied customers
97 f150: v6..exhaust is good, fuel pump and fuel filter..idles..revs
97 f150 4.2l v6, no power when load applied, exhaust is good, fuel pump and fuel filter just replaced. gets fuel, gets spark, idles and revs fine, just doesnt have any balls when i start to move. its … read more
AMEDEE
AMEDEE
FORD TECHNICIAN
28,500 satisfied customers
ford f150: V6..Pressure sensor..check engine light..it misfires onces
I have a ford f150 V6 4.2 motor and I just had the "ERG Pressure sensor" and the check engine light finally came off, but I still dont have good horse power and it misfires onces in a wile, what else … read more
AMEDEE
AMEDEE
FORD TECHNICIAN
28,500 satisfied customers
2001 ranger: 2.5 liter..gas peddle, it jumps forward, and when I let
I replaced the troddle control sencor on my 2.5 liter 2001 ranger, now when I touch the gas peddle, it jumps forward, and when I let off the peddle it throughs my head forward, I took it in a couple w… read more
AMEDEE
AMEDEE
FORD TECHNICIAN
28,500 satisfied customers
2001 Ford F150: O2 sensor..EGR Valve..so the service engine soon light
On a 2001 Ford F150 with a 4.2 Liter engine. What is required when you have the following codes: P0171 / System too lean Bank 1 P0174 / System too lean Bank 2 I have already changed the right side O2 … read more
Scottdagoalie
Scottdagoalie
Vocational, Technical or Trade Scho
1,663 satisfied customers
air filter..mass air flow..idle it surges and stalls..exhaust
I bought my van three months ago it has had a hesitation problem since I bought it so I changed the plugs and air filter. That didn't help so I took It to a shop, the mechanic said he thought it was t… read more
Chris (aka- Moose)
Chris (aka- Moose)
Technician
Vocational, Technical or Trade School
29,223 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x