2002 Ford Ranger Can't Figure out my Misfire Problem

Tiny
BGASS1421
  • MEMBER
  • 2002 FORD RANGER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 140,000 MILES
Ok, so I have had a misfire with cylinder 6 two separate times in 2 years. Both times I replaced all the spark plugs and wires (regular tune up). The code goes away for a while but the truck idles horribly, especially when I come to a red light. I change the oil regularly. I have changed the fuel filter, no change. I have changed the air filter, still rough idle. I cleaned the idle air control valve, and the MAF, and the throttle body. It still idles very rough but was not throwing codes for 2 months just rough idle. Now the check engine light sometimes comes on when I have driven the truck for a while and the engine is very warm, and it ONLY comes on when I am idling at a stop. It blinks until I take off again and then it goes away. I changed the cylinder 6 plug and I still have the problem! I have no idea what to do now!
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Monday, February 22nd, 2010 AT 11:54 AM

16 Replies

Tiny
RASMATAZ
  • MEMBER
Check the compression and injector for no. 6 cyl.
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Monday, February 22nd, 2010 AT 12:02 PM
Tiny
BGASS1421
  • MEMBER
I had a compression test done #1=115, #2=100, #3=110, #4=100, #5= 105, #6=110, I was told that was good. Im still stuck.
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Tuesday, February 23rd, 2010 AT 12:25 PM
Tiny
RASMATAZ
  • MEMBER
Engine running rough or misfiring can be cause by the following:

1. Defective spark plug.
2. Inadequate spark/coil, defective spark plug wire.
3. Lack of compression
4. False air leakage.
5. Faulty fuel injectors.
6. Insufficient fuel pressure.
7. Contaminated fuel.
8. EGR valve that is leaking.
9. Oxygen sensors.
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+1
Tuesday, February 23rd, 2010 AT 1:38 PM
Tiny
BGASS1421
  • MEMBER
Spark plugs and wires are new and good.
Compression check is good.
I only get the check engine light once in a while and only at idle when the engine is really hot. However the engine has a rough idle problem hot and cold, all the time, sometimes the idle is so bad, the truck feels like its about to die.
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-1
Tuesday, February 23rd, 2010 AT 1:50 PM
Tiny
RASMATAZ
  • MEMBER
Double check the IACV, EGR valve and TPS
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Tuesday, February 23rd, 2010 AT 1:53 PM
Tiny
BGASS1421
  • MEMBER
Ok, so I have not been able to double check those parts yet. HOWEVER I disconnected my MAF sensor, cranked the truck and she purred like a kitten, I have never seen an idle that smooth in this truck, when I hooked the MAF back up, rough idle again. I took the Maf off and cleaned it again. Still very rough idle. Any more thoughts? Do I need to get a new maf?
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Thursday, February 25th, 2010 AT 9:24 AM
Tiny
RASMATAZ
  • MEMBER
Check and test the wiring back to the computer for short or open if okay consider a new one
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Thursday, February 25th, 2010 AT 9:27 AM
Tiny
BGASS1421
  • MEMBER
Ok, so my buddy has the same truck as me but a year newer. His runs fine. I switched our maf sensors and no change. I guess it's not my maf. The idle is HORRIBLY rough, the engine is shaking severely. I pulled each plug wire off of the plugs to see if there was any change in idle. I noticed that there was no change when I pulled the wire for #6 (this is the one that sometimes throws a code) I also noticed that the idle does not change much at all when I pulled the wires of of the #4 plug and the #5 plug (of course not at the same time). So there is a pattern here, those plugs are on the same side of the engine. So I went and swapped out my new wires for some more new wires. No change. Currently horrible idle and no codes.
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Thursday, February 25th, 2010 AT 6:40 PM
Tiny
RASMATAZ
  • MEMBER
Check the engine compression both wet and dry tests
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Thursday, February 25th, 2010 AT 6:51 PM
Tiny
BGASS1421
  • MEMBER
Compression tests were done a couple of days ago, checked out good
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Thursday, February 25th, 2010 AT 6:58 PM
Tiny
RASMATAZ
  • MEMBER
Run an injection cleaner thru it and see what happens, also is the check engine light coming on or has flashed? If so try scanning for code/s.
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Thursday, February 25th, 2010 AT 7:03 PM
Tiny
BGASS1421
  • MEMBER
I have put some gum out in the gas for the injectors, we will see what that does. I only get a code every one in a while, when I come to a stop after the engine has been running for a while, the light will blink, when I take off, the light usually goes off. A couple of times it stayed on and I got it checked and it always says cylinder 6 misfire.
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Thursday, February 25th, 2010 AT 7:13 PM
Tiny
SCOTTY DEE
  • MEMBER
Pull the valve cover and see if a rocker arm is loose or if a valve is getting stuck. If that checks out, go ahead and do a cylinder leakdown test.
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Friday, February 26th, 2010 AT 9:02 AM
Tiny
BGASS1421
  • MEMBER
Ok, just an update on my cylinder 6 misfire. Remember, it only misfires when the weather is warmer and the engine has been running for a while. The misfire is ONLY at idle. I have been through 3 sets of wires and plugs now. I have changed the coil pack. I have changed the fuel filter, oil, and pcv valve. I have cleaned the MAF sensor and the IACV. My truck is not equipped with an EGR. I have swapped the injectors around. I am still getting the misfire in cylinder 6. I also had a compression test done and it was ok. I am LOST.
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Wednesday, March 10th, 2010 AT 7:26 AM
Tiny
CA2000RANGER
  • MEMBER
Mine is a 2000 Ranger with 93000 miles. The idle is rough and the check engine light comes on for a couple days then the light goes out and it seems to run fine for a while. Then it comes back again.

At the last smog test last month it showed a cylinder 6 misfire and a evap control valve problem. We changed the evap valve and re-did the test; passing this time. The mechanic said it probably needed a valve job to fix the problem.$$$$. The idle is not as bad as you describe yours, but I'd like to solve it sooner than later and if it can be done without opening up the engine, that'd be great. Oh, the mechanic did a compression test and found #6 was at about 70.
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Thursday, March 11th, 2010 AT 11:22 PM
Tiny
BGASS1421
  • MEMBER
Thanks for the info, I already had a compression test done and it checked out great in all valves. I am still clueless lol!
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Friday, March 12th, 2010 AT 4:44 PM

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