97 4.6l misfires
#1
Junior Member
Thread Starter
97 4.6l misfires
Hi guys new the forum world. But before anybody jumps me about starting another thread about misfires I have not seen one with my situation in the search. So here we go back in January I threw a rod threw my block, I finally decided to drop another motor in and just finished about 3 weeks ago. replaced all gaskets, plugs,and wires. I did not however replace coil packs due to the fact that when they were on the old motor they still worked fine. After replacing several sensors the newest was a 02 sensor a day before my misfires happen, trying to get rid of the check engine light. After replacing the o2 sensor on sunday evening, i finally drove it monday morning to work got about 6 miles from my house it started hesitating real bad with a loss of power with a blinking check engine light this happened for 2 miles and went away the rest of my 30 mile trip.The check engine light stayed one so I went and had the code pulled it was P0306. I checked for vaccum leak none to be found. So I switched coil packs from one dide to the other to see if it followed, it did not this time it was missing on cylinder 5. I am clueless I wouldnt think it would be a injector or coil problem due to the fact it jumped to a completley different cylinder. Any insight would help thanks.
#2
Senior Member
Hi guys new the forum world. But before anybody jumps me about starting another thread about misfires I have not seen one with my situation in the search. So here we go back in January I threw a rod threw my block, I finally decided to drop another motor in and just finished about 3 weeks ago. replaced all gaskets, plugs,and wires. I did not however replace coil packs due to the fact that when they were on the old motor they still worked fine. After replacing several sensors the newest was a 02 sensor a day before my misfires happen, trying to get rid of the check engine light. After replacing the o2 sensor on sunday evening, i finally drove it monday morning to work got about 6 miles from my house it started hesitating real bad with a loss of power with a blinking check engine light this happened for 2 miles and went away the rest of my 30 mile trip.The check engine light stayed one so I went and had the code pulled it was P0306. I checked for vaccum leak none to be found. So I switched coil packs from one dide to the other to see if it followed, it did not this time it was missing on cylinder 5. I am clueless I wouldnt think it would be a injector or coil problem due to the fact it jumped to a completley different cylinder. Any insight would help thanks.
#3
Junior Member
Thread Starter
Yes, but I figured out cylinder 5 misfire I must have accidently unplugged the injector when I was removing cylinder 6 wire to check continuity. The plug wire checked fine. But after I plugged the injector back in I reset code and took it for a drive it ran fine for about 5 miles and started misfiring again for a few miles at a time then clears up for a few then does it again. Check engine light started flashing so I pulled code again it was P0306. I have the old injectors from the old motor I am going to pull one and replace cylinder 6 along with checking the plug again I don't know what else to do besides that unless you guys have an idea.
#4
Senior Member
Yes, but I figured out cylinder 5 misfire I must have accidently unplugged the injector when I was removing cylinder 6 wire to check continuity. The plug wire checked fine. But after I plugged the injector back in I reset code and took it for a drive it ran fine for about 5 miles and started misfiring again for a few miles at a time then clears up for a few then does it again. Check engine light started flashing so I pulled code again it was P0306. I have the old injectors from the old motor I am going to pull one and replace cylinder 6 along with checking the plug again I don't know what else to do besides that unless you guys have an idea.
#6
Senior Member
The following users liked this post:
lucasradwanski (09-23-2015)
#7
Senior Member
Hey, -I've never done that before. Well admitted to it anyway
@ lucasradwanski- Two things ,
1. Make sure your ignition harness is well away from the AC accumulator. We have a tendency to not reconnect that correctly after playing with the harness , - moving things around. Well, not the connection, rather the bulk head position. It's easy to re position the ignition harness too close to the accumulator which can and has created ignition havoc due to a magnetic disturbance from the accumulator. These wires are foil wrapped/protected but not 100%. So make sure the ig harness isn't touching or even close to it. Since you say you didn't have a problem with these pacs before hand, - it makes this a good possibility. At times these wires can become damaged so check for that as well. Also, what guys have done is tie the ig wires back and away from the accumulator and the problem disappears. This goes for both Coil Pac and COP systems.
2. Without going into detail. - Make absolutely sure you running Motorcraft plugs in that 97.
3. Yes, it could be an injector, swapping may help determine, but it may not.
4. Check your EGR operation. In fact, to totally eliminate that from being problematic, slide a plate in between the EGR port totally blocking off the EGR valve from the throttle body elbow. Drive the vehicle around after reconnecting the battery. You will know pretty quick if the EGR was at fault.
5. Lastly, if all else has failed, you'll need to compression check #6 and compare results to at least two other cylinders. I have a write up if needed.
Okay, so that was more than two things. Should keep yuh busy for awhile tho.
@ lucasradwanski- Two things ,
1. Make sure your ignition harness is well away from the AC accumulator. We have a tendency to not reconnect that correctly after playing with the harness , - moving things around. Well, not the connection, rather the bulk head position. It's easy to re position the ignition harness too close to the accumulator which can and has created ignition havoc due to a magnetic disturbance from the accumulator. These wires are foil wrapped/protected but not 100%. So make sure the ig harness isn't touching or even close to it. Since you say you didn't have a problem with these pacs before hand, - it makes this a good possibility. At times these wires can become damaged so check for that as well. Also, what guys have done is tie the ig wires back and away from the accumulator and the problem disappears. This goes for both Coil Pac and COP systems.
2. Without going into detail. - Make absolutely sure you running Motorcraft plugs in that 97.
3. Yes, it could be an injector, swapping may help determine, but it may not.
4. Check your EGR operation. In fact, to totally eliminate that from being problematic, slide a plate in between the EGR port totally blocking off the EGR valve from the throttle body elbow. Drive the vehicle around after reconnecting the battery. You will know pretty quick if the EGR was at fault.
5. Lastly, if all else has failed, you'll need to compression check #6 and compare results to at least two other cylinders. I have a write up if needed.
Okay, so that was more than two things. Should keep yuh busy for awhile tho.
Trending Topics
#9
2003 F-150 King Ranch
#10
Junior Member
Thread Starter
Ok so I was in the process of trying everything you guys previously stated I discovered coolant in my number 6 spark plug well. I found a few bolts along that side of the intake manifold that needed to be re-torqued. I cleaned the well best I could let it idle for an hour to see if I could see a leak. I found none took it for a test drive its still misfing. I think im going to get some electrical cleaner and clean the old wet dielectric grease out of the wire and try it again. tomorrow and pointers, tips, or ideas. I have never run into so many problems with a vehicle in my life.