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Check Engine Light?

Tiny
CARADIODOC
  • MECHANIC
  • 33,916 POSTS
Two things to try are switching the number 6 injector with one from a different cylinder to see if the misfire moves to that other cylinder, and check the routing of the plug wires. If any are too close together, the current through one can induce a voltage spike into another one causing that plug to fire at the wrong time.

Misfires are detected by the rotational speed of the crankshaft slowing down momentarily. That is what allows us to feel it. At highway speeds that may not last long enough to be detected, but the misfire event will last longer at slower speeds and that may be the only time it is detected.
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
CARADIODOC
  • MECHANIC
  • 33,916 POSTS
Forgot to mention that many engines do not like fancy spark plugs or those from some manufacturers. As a test, try reinstalling the old plug in cylinder 6. If that stops the code from setting, check the new one's gap and brand. Check the new plug wire too or switch it with a different one. If the end wasn't fully seated, (we all do that sooner or later), the terminal can burn away leading to a misfire. That will take some time to show up.
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
PAUL SPAULDING
  • MEMBER
  • 1 POST
  • 2001 FORD RANGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 113,457 MILES
Rough idle even more when it is put ingear. Very rough at speeds 45 to55. Check engine light is also on. What could be the promblem?
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
MERLIN2021
  • MECHANIC
  • 17,250 POSTS
First thing you need to do is have the codes read, Post the results with the code number(s). Even if the service engine light is not on, there should be freeze frame data stored.
If it won't make it, buy a cheap scanner, they can be had for 30-40 dollars, a good investment, since they cover all cars sold in the USA from 96 on.
If the light is blinking, it means possible damage to the Catalytic converter. Misfires. Service it right away!
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
CAMPERMAMA
  • MEMBER
  • 9 POSTS
  • 2001 FORD RANGER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 85,000 MILES
Hi, my truck just started doing this. It runs fine but when at idle (like at a light or just stopped) it lopes. The check engine light is on and it is sucking gas like crazy.
I am buying a scan tool to day to get the codes. But an wondering what you think about this. Thanks!
Stacey
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
BLACKOP555
  • MECHANIC
  • 10,371 POSTS
Really would not like to jump to conclusions till the codes are scanned.

But if I was to guess I would be thinking o2 sensor code.
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
CAMPERMAMA
  • MEMBER
  • 9 POSTS
I got a scan tool but it won't work on the ranger! No codes no messages nothing! I tried it on an older car and it worked fine. Any ideas?
I am going crazy, I need to fix this truck and now I can't even get the codes.
Thanks for your help!

Stacey
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
CAMPERMAMA
  • MEMBER
  • 9 POSTS
Ok found out the scanner wouldn't work because of a blown fuse!
These are the codes I got.

P0102 - MAF or VAF A circuit low input
P0171 - Systen too lean (bank 1)
P0174 - System too lean (bank 2)
P0300 - Random/multiple cylinder misfire detected (I don't believe thia one).
P1504 - Idle air control circuit

Like I said it runs fine just burning gas like crazy and lopes at idle.
Any ideas?
Thanks!
Stacey (single mom trying to help daughter out)
I was going to try cleaning the MAF and IAC today, do yu think this will help?
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
BLACKOP555
  • MECHANIC
  • 10,371 POSTS
Deffintely recommend cleaning the maf sensor see if you can clear up that code, the maf sensor can cause the o2 sensors codes and the missfire code to be thrown.

Low input means its not sending as high a signal indicating too little air coming in which is likely a missread from a dirty sensor, when in actuallity it is getting too much air messing up the other codes.

Clean the iac see if that helps the bad idle, could be the maf sensor, on hook it, does it idle better?
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
CAMPERMAMA
  • MEMBER
  • 9 POSTS
So it turned out to be a bad MAF, I replaced it, then I drove the truck. Check engine light came back on. Replacing the MAF cleared 4 out of 5 codes. The one code I have now is P0300, misfire.

The idle is rough and does feel like a misfire. Going to check the plugs today. If not the plugs what would your second guess be?

I have lost 4 lbs fretting over this for 5 days now. Thanks for your help!

Stacey
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
BLACKOP555
  • MECHANIC
  • 10,371 POSTS
Check the ignition coil also. Could be causing that problem.

Try unhooking various sensors and running it to see if you can cure the missfire.
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Friday, November 27th, 2020 AT 10:08 AM (Merged)
Tiny
STEVE H.
  • MEMBER
  • 1 POST
  • FORD RANGER
I have a 2001 Ford Ranger XLT. 3.0 liter V-6 Automatic w/overdrive. 133,000 miles. I have had no problems with this truck until recently. Other day was driving to work & check engine light came on and engine started running rough. There seems to be a vibration in the motor. It doesn't die, there is just a noticeable vibration when the engine is running. I have made a visual inspection of engine & see nothing out of the ordinary. I also replaced the spark plugs. Nothing changed. I understand the most logical thing to do would go have the codes pulled rather than continuing with this system of elimination, but until then, what does this sound like to you? Also, the speedo needle has been jumping when at idle between 10-15 mph. Not all the time, but this started when the engine started running rough. Any ideas?
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Friday, November 27th, 2020 AT 10:42 AM (Merged)
Tiny
TOBYU
  • MEMBER
  • 89 POSTS
A flashing check engine light means it has a bad steady miss.A cylinder basically not firing at all.
It sounds like a bad plug wire. How were the ends that snap onto the plugs when yo did the plugs?
The jumping speedo could very well be spark energy jumping out of the insulation of the wire and shunting into the wiring and messing with the gauges.
Look at wires at night with under hood light out. Shake the wires a bit. Look for high energy current running/jumping/arcing around.
I would replace them, or ohm them out with a DVOM to make sure there is not one with high resistance or even a total break in conductivity between the ends.
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Friday, November 27th, 2020 AT 10:42 AM (Merged)
Tiny
RASMATAZ
  • MECHANIC
  • 75,992 POSTS
Could be the throttle position sensor going whack-We won't know till you get a read out of the OBD2. You can take it to autozone and get read for free and who knows they might just hook you up on the spot and send you home happy.
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Friday, November 27th, 2020 AT 10:42 AM (Merged)

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