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My check engine light is on?

Tiny
NESIECAT
  • MEMBER
  • 1999 FORD RANGER
My 99 ranger 6 cyl 3.0 4x4 mileage 103000 has a vacuum leak. I don't even know how to start to fix it. When I am running my heat or air, and I accelerate, the air stops blowing from the air vents and starts blowing through the defrost vents. When I let off the gas the air starts blowing through air vents again. My check engine light is on as well, could that be why the check engine light is on?
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Friday, August 3rd, 2007 AT 4:51 PM

39 Replies

Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
Interesting.. Start off by getting the codes

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

This will put you onto the trail of the source. Should it turn out to be vacuum related, a smoke machine will help flush it out.
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Friday, August 3rd, 2007 AT 7:54 PM
Tiny
FREEDOM0327
  • MEMBER
  • 2 POSTS
  • 1999 FORD RANGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 85,500 MILES
I have a 99 Ranger. Just had fuel injection system worked on less than 6 months ago. I also had a vacuum leaked that was repaired. My Truck now shakes when started and driving and only goes up to 35 and then shakes even more. It shakes at all stops. The check engine light is stuck on solid. What could the problem be.

Steve
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Friday, November 27th, 2020 AT 10:18 AM (Merged)
Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
You need to start with finding what codes are in the pcm to start off with.

Are the plugs original?
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-1
Friday, November 27th, 2020 AT 10:18 AM (Merged)
Tiny
FREEDOM0327
  • MEMBER
  • 2 POSTS
I am not sure about the plugs I bought it used from a used car dealer. Do I need to take it to a shop for a diagnostics test to get codes?
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Friday, November 27th, 2020 AT 10:18 AM (Merged)
Tiny
SERVICE WRITER
  • MECHANIC
  • 9,123 POSTS
You have several options for retreiving the codes.

Autozone parts store will do it for free.-This just gives the code #. A pretty general guess at this point.

You can buy a scanner and read the codes. Before you buy a scanner, decide how serious this is that you solve it.

You can bring it to a shop that professionals do this on a regular basis and pay them to troubleshoot it.

IT sounds like a misfire. IT is a guess that plugs maybe worn enough to cause a mis-fire. But that is a leap of faith.
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Friday, November 27th, 2020 AT 10:18 AM (Merged)
Tiny
RICKYPETERS
  • MEMBER
  • 2 POSTS
  • 1999 FORD RANGER
  • 6 CYL
  • 4WD
  • MANUAL
  • 190,000 MILES
My check engine light is and and wont turn off. It says my O2 sensor is bad, so I changed it then it sadi the next one was bad and so fourth until I changed all three os sensors on my truck. I unplugged the battery over night to reset the computer and still the light is on. After reseting the computer, putting all new o2 sensors in the truck, the computer still say the o2 sensor is bad. Ive even changed out the new sensors with different new sensors just to make sure those weren't faulty. Is there some other part that is sending up that code that I could change?
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Friday, November 27th, 2020 AT 10:20 AM (Merged)
Tiny
BLUELIGHTNIN6
  • MECHANIC
  • 16,542 POSTS
Hello and thanks for the donation!

A dirty or faulty catalytic converter will often throw the oxygen sensor fault code. Have the cat. Converter flow tested and ensure it is working properly.
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Friday, November 27th, 2020 AT 10:20 AM (Merged)
Tiny
RETIRED DR. PHIL
  • MEMBER
  • 1 POST
  • 1999 FORD RANGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 111,200 MILES
Check engine came on, truck runs fine, no reduction in performance or gas milage.1999 ranger w/4.0 EFI engine. Any way to check problem without giving FORD service a million bucks for diagnosis?
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Friday, November 27th, 2020 AT 10:20 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
The "check engine" light is an indicator for a system that monitors many electronic functions in the system, also called the "malfunction indicator lamp" (MIL). It can come on for any of hundreds of different causes from any of the systems that the computer monitors. Some are very important and can lead to further component or engine damage and some are emissions related not as serious but still a problem and need to be repaired.

Your first step is to have the computer scanned to retrieve the trouble codes that were set when the check engine light came on. Those codes will give you specific information about what the computer saw and will get you pointed in the right direction to find your problem. With a 1996 or newer and some 95 cars and you have an AutoZone or Advanced auto parts in your area, they will read them for free. Once you have these code numbers, we can be a lot more specific about what your problem may be.
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Friday, November 27th, 2020 AT 10:20 AM (Merged)
Tiny
DAVE'S BIG BACKYARD!
  • MECHANIC
  • 262 POSTS
Yes you must have it scaned before you can even start to know whats wrong with it.
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Friday, November 27th, 2020 AT 10:20 AM (Merged)
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
I don't know how that overpost was any benefit to anyone.
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Friday, November 27th, 2020 AT 10:20 AM (Merged)
Tiny
DAVE'S BIG BACKYARD!
  • MECHANIC
  • 262 POSTS
I was just trying to support what you were saying. Im sorry.
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Friday, November 27th, 2020 AT 10:20 AM (Merged)
Tiny
JONISAN
  • MEMBER
  • 1 POST
  • 1999 FORD RANGER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
I have a check engine light on. Had it checked and the code is a loose gas cap. The gas looks just fine. Is there something else I can look for.
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Friday, November 27th, 2020 AT 10:21 AM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
I have never seen a loose gas cap code what is the exact code numbers you have not code descriptions? Also how do you know the gas cap is good did you have it tested?Did you inspect the gas cap seal for cracking?
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Friday, November 27th, 2020 AT 10:21 AM (Merged)
Tiny
MRPIPPY
  • MEMBER
  • 2 POSTS
  • 1999 FORD RANGER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 90,000 MILES
I bought this new in 99 I have a ford ranger xlt with a 6cyl in it the check engine light is on I took notice that when it gets very cold out the check engine light goes out for a while.I really had no problems with the truck until now.I do general maintenance on it chage oil wires plugs etc it idles kind of rough and my gas milelage is terrible
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Friday, November 27th, 2020 AT 10:21 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
I strongly recommend that you check our "Check Engine Light" article at
https://www.2carpros.com/articles/service-engine-soon-or-check-engine-light-on-or-flashing

Have the computer scanned for code/s-you have a problem within the engine management system that caused the CEL to turn on-This is your starting point of diagnosis,finding out what's going on.
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+1
Friday, November 27th, 2020 AT 10:21 AM (Merged)
Tiny
PROTECH1980
  • MEMBER
  • 901 POSTS
Get the vehicle scanned for codes, that is where we will start diagnoses, that will tell us what made the light come on and lead us in the direction for repair.
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Friday, November 27th, 2020 AT 10:21 AM (Merged)
Tiny
MRPIPPY
  • MEMBER
  • 2 POSTS
I had it checked but the say it could be one of three censor is there any way of narrowing this down without guessing.
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Friday, November 27th, 2020 AT 10:21 AM (Merged)
Tiny
CJ MEDEVAC
  • MECHANIC
  • 11,004 POSTS
Just to keep things going--I will jump in--They will want to know what the codes are (The exact #'s &/or letters)--So they can give you possibilities to check/ test etc--OK, I butt out now--The Medic
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Friday, November 27th, 2020 AT 10:21 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Medicine man-now you're making sense-we cannot do it w/o them numbers its popping up during change of weather condition we have to catch it while on the run with the scanner/PID's data-If you wish you can take over and me and Mr. Pro we'll kick back and observe-Good Luck
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Friday, November 27th, 2020 AT 10:21 AM (Merged)

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