How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Amedee Your Own Question
Amedee
Amedee, Toyota Technician
Category: Toyota
Satisfied Customers: 25605
Experience:  ASE certified tech advanced level specialist. Wisconsin certified emissions state inspector
279429
Type Your Toyota Question Here...
Amedee is online now
A new question is answered every 9 seconds

I have a 2003 Toyota Camry LE - 4 cyl. Car threw CEL code

Customer Question

I have a 2003 Toyota Camry LE - 4 cyl.
Car threw CEL code P0171 last Thursday.
I cleaned MAF sensor, then replaced sensor over the weekend. disconnected (+) battery terminal for 5 mins. drove car this morning and now the engine is surging/hesitating on throttle past 1/2 way. anything below 1/2 throttle, car runs fine and normal. not sure what else could be the issue.
Submitted: 1 month ago.
Category: Toyota
Customer: replied 1 month ago.
Forgot to add that car has been running a little louder and almost knocking over past week before the CEL. I am assuming this is due to the engine running lean...?
Expert:  Amedee replied 1 month ago.

Hello and welcome!

My name isCustomerand I can assist you with your question.

Expert:  Amedee replied 1 month ago.

I am very sorry your having this issue with your vehicle.

I will try my best to answer all of your questions.

However, before we get started, please let me mention a few things.

1. If at any point you would like to speak on the phone, please feel free to request a phone call on your end and I can call you right away.

2. If you dont understand any technical terms or anything that I mention (component tests or theory or operation), please let me know and I will provide you with a more in debt explanation or answer.

3. Please understand that I am here to help you anyway I can.

When does the engine surge? At idle or when accelerating?

Customer: replied 1 month ago.
Thank you. please let me know when you have had a chance to review
Expert:  Amedee replied 1 month ago.

When does the engine surge? At idle or when accelerating?

Customer: replied 1 month ago.
it does this when accelerating and only when the gas pedal is pressed more than 1/2 way.
Expert:  Amedee replied 1 month ago.

Thank you for that information.

If the mass air flow sensor has been replaced, then I would suspect an air/vacuum leak. I would inspect the air intake snorkel for cracks/rips.. anywhere that air can enter the engine not accounted for by the mass air flow sensor.

If your sure there are no air or vacuum leaks and the mass air flow sensor is reading correctly, I would suspect a faulty oxygen sensor/air fuel ratio sensor before the converter.

Customer: replied 1 month ago.
is there a way to check this besides the naked eye? in the event there is a small tear somewhere that cannot be seen?
Expert:  Amedee replied 1 month ago.

Yes sir there is. The correct test would be to smoke test the intake system using a smoke machine to locate/pinpoint any small hard to locate leaks.

Customer: replied 1 month ago.
ok, is there a kit or something that could be picked up at local auto parts store to perform this test?
Expert:  Amedee replied 1 month ago.

Not that I am aware of. The only smoke machine I know of is the smoke pro which is very expensive. Your best bet would be to have a shop smoke test the intake system for you so you don't have to purchase one.

Expert:  Amedee replied 1 month ago.
Customer: replied 1 month ago.
ok, I will see what I can find out and get back in touch after checking for air leak tests
Expert:  Amedee replied 1 month ago.

Sounds good!

I am glad I can help!

It has been a pleasure working with you. Please don't forget to honor your good faith deposit by rating my answer as "5 STAR SERVICE" for assisting you today.

Keep in mind, we can still continue this conversation at no further cost to you even after you rate my answer. Just reply back to me using this page and I will get it and get back to you ASAP!

Also, if you are a member or if you have a subscription to the site, you still need to rate my answer in order for me to get credit for assisting you with your question.

Please let me know if you have any further questions.

Customer: replied 1 month ago.
Hi, yes. it still is running rough and almost sounds like a diesel engine when idling and/or running in general. I just changed the oil this weekend, so it has enough oil.
Expert:  Amedee replied 1 month ago.

Hello!

Was the intake smoke tested for vacuum leaks?

Customer: replied 1 month ago.
We could not find any leaks last night. hesitation has stopped on acceleration. but it is still running rough/loud.
Expert:  Amedee replied 1 month ago.

Was the mass air flow sensor replaced?

Expert:  Amedee replied 1 month ago.

Was the oxygen sensor replaced?

Expert:  Amedee replied 1 month ago.

It will still run rough if you don't replace the faulty part. :)

Expert:  Amedee replied 1 month ago.

Are you sure the engine is not making noise?

What about the exhaust system?

I dont know because I cannot hear your vehicle.

Can you send me a video?

One thing is for sure, if you did not replace anything, it will still be loud and run rough.

Customer: replied 1 month ago.
the MAF sensor was replaced over the weekend. it was not hesitating today when driving around, but it still is running rough.
Expert:  Amedee replied 1 month ago.

Is the engine misfiring?

Customer: replied 1 month ago.
it does not sound like that. it is just running louder than it has previously in the past. almost sounded like a diesel engine.
Expert:  Amedee replied 1 month ago.

Your exhaust may be leaking or there may be internal engine damage causing this noise.

I dont know.. I CANT HEAR IT.

Can you please send me a video so I can hear it??

Customer: replied 1 month ago.
ok, i will get one tonight. thanks!
Expert:  Amedee replied 1 month ago.

Your welcome.

I will send over my phone number now so you have it.

You can send it directly to my phone

Customer: replied 1 month ago.
here is the recording of the engine with the noise described above.
Expert:  Amedee replied 1 month ago.

Hello!

I cannot open the file for some reason.

Can you send it to my phone?

Customer: replied 1 month ago.
you may need to use a computer to access. it would not let me upload an m4a file.
Expert:  Amedee replied 1 month ago.

I am very sorry, I just have the one computer and my phone. :/

Customer: replied 1 month ago.
here is the sound
Customer: replied 1 month ago.
see if that one opens.
Expert:  Amedee replied 1 month ago.

Nope.

Can you post it on youtube and then send me the link?

Customer: replied 1 month ago.
I dont have a youtube account. do you have an email that I could send it to?
Expert:  Amedee replied 1 month ago.

I just sent it over.. but still, I wont be able to open it on my computer unless you change the file

Customer: replied 1 month ago.
ok, I resent the file. did you receive it? I recorded that while it was idling.
Expert:  Amedee replied 1 month ago.

YES, I got it and I replied back to you. Check your email.

Customer: replied 1 month ago.
ok, how would I see where its coming from? just popping hood and seeing when it gets louder?
Expert:  Amedee replied 1 month ago.

That's correct. That's exactly what a mechanic would do to pinpoint the problem.

Customer: replied 28 days ago.
Sent over new files.
Expert:  Amedee replied 28 days ago.

I responded already. :)

Customer: replied 23 days ago.
Appointment at shop on Wednesday to look at the engine. Will see what they say.
Expert:  Amedee replied 23 days ago.

Sounds good!

Customer: replied 18 days ago.
they are not sure but said it could be the intake manifold and would need to replace it to see?? Does that even sound right?
Expert:  Amedee replied 18 days ago.

Hello!

Was it the intake manifold assembly or just the intake manifold gasket?

YES, it does sound right. Anything that is leaking vacuum van cause a lean condition and flag this lean diagnostic trouble code P0171.