New COPS installed
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From: Louisville, Kentucky
New COPS installed
A while back I changed the spark plugs in my truck for the first time. Thanks to Racerguy's thread it went smoothly. The rough running and the high load low RPM miss went away and I was a happy owner again.
Well the high load low RPM miss slowly crept back in. The battery was still the orignal one for the truck and it was getting weak, the gauges would occassionally sweep all the way to full scale and back when starting the truck. So I had it replaced with a new MotorCraft battery. That made a marked difference in the idle but the high load low RPM missfire still nagged at me till I finally had enough of it.
I had purchased a new set of COPs from Performance Distributors, a site sponsor some time ago. Their product called Sultans of Spark is a aftermarket high output COP. I decided to take the time to install them and fix the problem for good.
Once again the process went smoothly. The plugs have to be re-gapped to .065" due to the longer spark duration provided by these coils. Got it all buttoned up and fired it up.
There was a miss at idle that wasn't there before. Soon the CEL came on and a P0357 trouble code showed up. In addition to the miss, the AC no longer got cold and I thought that I had knock a connector off somewhere.
After looking up the trouble code and determining that there was a problem with cylinder 7, I checked under the hood and found that I had not reconnected the wiring connector to the COP on that cylinder. Plugged it in and the miss went away. To my surprise, the AC went back to normal operation too! It is now running like a new truck again, no signs of rough idle or of the high load low RPM miss either. it cranks and starts much faster too with the new battery. I am still wondering what the connection is between the AC and the unplugged COP!
Well the high load low RPM miss slowly crept back in. The battery was still the orignal one for the truck and it was getting weak, the gauges would occassionally sweep all the way to full scale and back when starting the truck. So I had it replaced with a new MotorCraft battery. That made a marked difference in the idle but the high load low RPM missfire still nagged at me till I finally had enough of it.
I had purchased a new set of COPs from Performance Distributors, a site sponsor some time ago. Their product called Sultans of Spark is a aftermarket high output COP. I decided to take the time to install them and fix the problem for good.
Once again the process went smoothly. The plugs have to be re-gapped to .065" due to the longer spark duration provided by these coils. Got it all buttoned up and fired it up.
There was a miss at idle that wasn't there before. Soon the CEL came on and a P0357 trouble code showed up. In addition to the miss, the AC no longer got cold and I thought that I had knock a connector off somewhere.
After looking up the trouble code and determining that there was a problem with cylinder 7, I checked under the hood and found that I had not reconnected the wiring connector to the COP on that cylinder. Plugged it in and the miss went away. To my surprise, the AC went back to normal operation too! It is now running like a new truck again, no signs of rough idle or of the high load low RPM miss either. it cranks and starts much faster too with the new battery. I am still wondering what the connection is between the AC and the unplugged COP!
Last edited by KingRanchMan02; Sep 29, 2009 at 03:00 PM. Reason: Added more.
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Joined: Jun 2004
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From: Pelahatchie, MS
I thought it was just me. I have an 02 F150 with a 5.4L. I just put a used engine in it, and left one of the COPs unplugged (unintentionally, of course). It was cylinder #4. I fired it up, and it had a miss in it that only got worse, and the a/c compressor would never cut on at all. I pulled the codes, found 1 for that cylinder, checked it, slapped myself on the forehead, plugged it up, and the miss went away. The a/c started working at the same time. I figured it was a fluke and dismissed it...... until now.....
Post Fiend
Joined: Feb 2000
Posts: 11,496
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From: Kansas
I had a misfire at idle but no codes. Truck had 120K on it and figured it was time to replace the COPS. Replaced all of them and checked them for resistance. All checked out. Knew it was time to replace the front O2 sensors so went ahead and did that, checked for vacuum leaks and cleaned the MAF.
Now she's really mad.
Check engine light is on showing 4 codes the last time I checked it. All indicating either a slow O2 reading or a lean condition and the miss is worse but it comes and goes as it did before.
Now she's really mad.
Check engine light is on showing 4 codes the last time I checked it. All indicating either a slow O2 reading or a lean condition and the miss is worse but it comes and goes as it did before.
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On the AC thing, i would guess if the computer sees a MAJOR miss fire, it kicks out the accessories like AC to help the truck idle better and get a little more power in case you need to stumble home. I know when the motor overheats, the computer turns off injectors to keep motor at lower power and try to cool motor donw.
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Fleet Mechanic
Joined: Nov 2000
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From: In my House
I think Steve isright...the motor went into whats called "fail safe" cooling mode, and the computer thinks the truck is overheating, so it shuts down the ability to have A/C and it may also take it a step further and limit your speed to 55mph.
Rich
Rich
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Joined: Dec 2001
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From: Louisville,Ky.
Yep ,the PCM shuts down unneeded accessories in limp mode.
Performance Distributors has high quality stuff for sure, I have their HEI dizzy and Live Wires on my 63 F100 and it runs much better than the Duraspark ignition that I added when I installed the 351W in it.
Performance Distributors has high quality stuff for sure, I have their HEI dizzy and Live Wires on my 63 F100 and it runs much better than the Duraspark ignition that I added when I installed the 351W in it.
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From: Louisville, Kentucky
I don't think it was "fail safe" mode. Power was down by one cylinder but it wasn't under powered by any means. I did not get it to the highway before I found the problem so I can't tell you about the speed being limited.
Elder User
Joined: Jun 2004
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From: Pelahatchie, MS
Same thing with mine KingRanch. I took it to town with that miss, and my speed wasn't limited. It did everything it was supposed to, except it had a bad miss and no a/c. When I got home, pulled the codes, and plugged that COP up, everything cleared right up and the a/c has been working fine ever since....
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KingRanchMan02
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Nov 8, 2006 08:46 AM
