Random misfire codes

Blackened300a

Blackened300a

Sinister with style
Just recently this has been happening. I took the car out 3 weeks ago to a car meet and on the way there, the check engine light came on for #3 cylinder misfire and a misfire under 1K RPMs. I didn't feel anything from the engine and it idled smooth. I cleared the code and it didn't come back on.

I took the car out last weekend and no codes and no issues at all. Last night I take the car out and I get a check engine light for misfire on cyl #5 and a P3060 code which I can't find anything online about what it is. It seems to be a catalyst code which I think may be related to the misfire. I cleared it and then proceeded to drive the car another 50 miles and the code never came back and the engine felt smooth the entire time even before the light came on.

The plugs have all been replaced with new NGKs when I did the blower install 3 years ago and maybe less then 3000 miles, the coils were all replaced at the same time about 4 years ago and 3500 miles using motorcraft coils, the wiring harness behind the head is secure and not rubbing so that's ruled out, the injectors were flowtested low mile 39lb with less then 10k miles total, I can't figure why the misfire codes would randomly jump from one bank to the other and the engine idles and runs smooth. I don't think coils would all start to fail at the same time, could this be MAF related or fuel?

Thanks for any info.
 
Check your main engine harness, mine had some oxidation on some of the terminals a few years ago and cleaning them up rid my weird misfire issues.

I've also had to repair an on off miss on Cyl 4 due to how the wiring turns to plug into the coil and found one of the wires had finally pinched in half at the bend.


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justbob said:
Check your main engine harness, mine had some oxidation on some of the terminals a few years ago and cleaning them up rid my weird misfire issues.

I've also had to repair an on off miss on Cyl 4 due to how the wiring turns to plug into the coil and found one of the wires had finally pinched in half at the bend.


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I actually checked the main harness plug recently because my center console power point stopped working and there was no corrosion and clean contacts. Im going to wait til the next time a code comes up and see if it jumps to another cylinder. I just find it odd that it's misfiring from bank to bank and the engine is running smooth the entire time.
 
Code for the Fusion, but codes can be generic. Might be worth checking into, symptoms seem similar. Also noted a C-3060 code can be related to a failing catalytic converter, check the sensor for trouble.

Symptoms

Symptoms of a P3060 Ford Fusion diagnostic trouble code may include:
  • Vacuum leak on the engine
  • Reduction in engine performance, especially at low RPM levels
  • Engine surge
  • The light may stay on or light intermittently as the DPF regenerates. The engine will be sluggish on acceleration.

Possible Causes :


  • Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
  • Low fuel pressure caused by a clogged filter, failing fuel pump, failed fuel pressure regulator or clogged or leaking injectors.
  • Rarely - faulty Powertrain Control Module (PCM-programming required after replacement)
 
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The only other thing I'm leaning towards is a tank of bad gas. I only got 240 miles to a tank full this fill up when I'm usually 325 to a tank. I'm also on the same tank full that I got two random misfire codes so it's making it suspect. I put gas in it last night so let's see if that improves it.
 
Blackened300a said:
The only other thing I'm leaning towards is a tank of bad gas. I only got 240 miles to a tank full this fill up when I'm usually 325 to a tank. I'm also on the same tank full that I got two random misfire codes so it's making it suspect. I put gas in it last night so let's see if that improves it.
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How do you get 325 to a tank with a Blower? WTF
 
Paul, check the harness at the rear of the drivers side cam cover. It's been known to rub on the long bolt there. I cover the bolt with a rubber vacuum cap.
 
Blackened300a said:
Just recently this has been happening. I took the car out 3 weeks ago to a car meet and on the way there, the check engine light came on for #3 cylinder misfire and a misfire under 1K RPMs. I didn't feel anything from the engine and it idled smooth. I cleared the code and it didn't come back on.

I took the car out last weekend and no codes and no issues at all. Last night I take the car out and I get a check engine light for misfire on cyl #5 and a P3060 code which I can't find anything online about what it is. It seems to be a catalyst code which I think may be related to the misfire. I cleared it and then proceeded to drive the car another 50 miles and the code never came back and the engine felt smooth the entire time even before the light came on.

The plugs have all been replaced with new NGKs when I did the blower install 3 years ago and maybe less then 3000 miles, the coils were all replaced at the same time about 4 years ago and 3500 miles using motorcraft coils, the wiring harness behind the head is secure and not rubbing so that's ruled out, the injectors were flowtested low mile 39lb with less then 10k miles total, I can't figure why the misfire codes would randomly jump from one bank to the other and the engine idles and runs smooth. I don't think coils would all start to fail at the same time, could this be MAF related or fuel?

Thanks for any info.
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fastblackmerc said:
Paul, check the harness at the rear of the drivers side cam cover. It's been known to rub on the long bolt there. I cover the bolt with a rubber vacuum cap.
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:fishslap:
 
I left out something that I didn't think as anything major. Recently my engine has been having a "crank no start" issue at random times. It's happened 3 times where the engine would just crank over and over but not start. I would let off the key, hit it again and it would fire right up. Going with the random hard starts, bad gas mileage, and now the misfire codes, I'm leaning towards a faulty crank position sensor. I ordered a new motorcraft one up and see what happens.
 
Blackened300a said:
I left out something that I didn't think as anything major. Recently my engine has been having a "crank no start" issue at random times. It's happened 3 times where the engine would just crank over and over but not start. I would let off the key, hit it again and it would fire right up. Going with the random hard starts, bad gas mileage, and now the misfire codes, I'm leaning towards a faulty crank position sensor. I ordered a new motorcraft one up and see what happens.
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I was saying crank sensor in my mind before I finished reading your post , another members car was doing the exact same thing and it turned out to be the crank sensor.
 
Update......

Swapped out the crank position sensor this morning. I drove the car about 30 miles, hard throttle, light throttle, sitting in traffic and open road, no check engine light.

I also noticed the engine started faster, idle is much smoother, I had a slight shudder when the car would idle at a traffic light, that's cleared up, the gas gauge did not move after driving the car hard. So gas mileage is definitely back to normal and I have a noticeable amount of power back in the car.

Before it was feeling sluggish which I thought was because of the heat and humidity. I took it out today and it spins tires at 1/4 throttle and pulls so much harder through the gears. This sensor may have been bad for quite a while for all I know and the misfire codes finally brought it to light. I'll drive the car some more to be certain but overall the engine feel so much smoother and drivability feels much better.
 
This problem is not solved.
I’m still getting a misfire code on cylinder #5. It started out with #3 and #5 misfires but a coil swap on #3 took care of that and that code never came back.

I’ve swapped the spark plug from #5 to cylinder #6, new coil, went back to the stock coil connector, ECM was sent out, tested and came back with nothing wrong with it, and the crank position sensor was replaced.
It’s totally random, before it was under 1K RPMs, now it’s under normal driving. A few weeks ago I put over 200 miles on the car with no codes or issues, then the light came on. I checked the coil to make sure it’s connected and I got a pending code for cyl #5 within 100 miles.
The engine runs smooth and has all its power, just keep getting this code. Any idea? It’s nearly a year that I been chasing this and I can’t get the car inspected because the CEL comes on before the monitors can set.

Thanks for any info.
 
Blackened300a said:
I left out something that I didn't think as anything major. Recently my engine has been having a "crank no start" issue at random times. It's happened 3 times where the engine would just crank over and over but not start. I would let off the key, hit it again and it would fire right up. Going with the random hard starts, bad gas mileage, and now the misfire codes, I'm leaning towards a faulty crank position sensor. I ordered a new motorcraft one up and see what happens.
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Had this situation happen with my previous Mustang. Load tested the battery and it was borderline, even after a full charge. It was explained to me that within the power distribution scheme of things, power goes first to the starter then the ecm - weak battery will turn over the motor but will fail to power up the ecm correctly.

Repeated attempts may prime the battery a bit to coax out enough power to light up the ecm. New, fully charged battery corrected the issue. Whenever I 'fully charge' a battery for testing, I 'top it off' with a Battery Tender or any similar type 'smart charger' as they will push the battery to 'full capacity' vs. about 80% for the alternator and standard chargers.
 
MyBlackBeasts said:
I Got 400ish highway to a tank with the canned Trilogy tune. 24mpg.

300 now after dynotune, 17mpg highway.
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Please tell us the differences in performance/feel between the 'canned' tune' and the dyno tune. I was talked into a $600 dyno tune on my '98 and it honestly didn't 'feel' any different than the 'canned tune' (chip) I bought from Superchips - my mileage went down also. Canned Superchips tune on my '05 and burning 93 E0 returned 27mpg highway driving 70-80mph through the VA and WVA hills (trip computer) on my Michigan trip to retrieve the Marauder this past March.
 
Invective said:
Had this situation happen with my previous Mustang. Load tested the battery and it was borderline, even after a full charge. It was explained to me that within the power distribution scheme of things, power goes first to the starter then the ecm - weak battery will turn over the motor but will fail to power up the ecm correctly.

Repeated attempts may prime the battery a bit to coax out enough power to light up the ecm. New, fully charged battery corrected the issue. Whenever I 'fully charge' a battery for testing, I 'top it off' with a Battery Tender or any similar type 'smart charger' as they will push the battery to 'full capacity' vs. about 80% for the alternator and standard chargers.
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I haven’t had the hard start issue in over a year. The battery is only 2 years old and it’s starting up fine every time. Just misfire issue is the only problem.
 
Blackened300a said:
The only other thing I'm leaning towards is a tank of bad gas. I only got 240 miles to a tank full this fill up when I'm usually 325 to a tank. I'm also on the same tank full that I got two random misfire codes so it's making it suspect. I put gas in it last night so let's see if that improves it.
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This was what I was thinking. Bad gas... Have you burned through this tank, or added a gas treatment (Seafoam or Redline)?
 
1Marauder said:
This was what I was thinking. Bad gas... Have you burned through this tank, or added a gas treatment (Seafoam or Redline)?
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I’ve went several tanks of gas and still getting the single cylinder misfire. I’m taking the car out tonight after swapping another coil in last night and see if it pops the code or maybe I’ll get lucky and solved my issue. I’m not holding my breath though.
 
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