intermittent miss usually under load COP?
06-25-2009, 10:41 PM
#1
Thread Starter
Join Date: Jun 2009
Location: CA
Posts: 4
intermittent miss usually under load COP?
Got an 01 stage 2 Roush Vert auto. I was cleaning up the engine compartment a few weeks ago and afterward, it started to develope a miss. I figured I got some water where it shouldn't be so I let it idel to dry out, and then dried all the inj plugs and COP plugs with compressed air.
Idles great but has a nasty miss under a load. When I get on it the miss increases, also at cruise it has a tendency to miss. At higher RPM it appears to run OK. As the engine warms up, it seems to get worse. it is especially bad under a load at lower RPM. I have changed the plugs with no effect. I have disconnected the the injectors and COP on each cylinder at idle with no real result. I have listened to each injector with a stethoscope and they are opening like they are supposed to. One may be clogged, but I'm leaning to the COP. I may buy a new one tomorrow and replace one at a time and see what happens.... Any suggestions?
Idles great but has a nasty miss under a load. When I get on it the miss increases, also at cruise it has a tendency to miss. At higher RPM it appears to run OK. As the engine warms up, it seems to get worse. it is especially bad under a load at lower RPM. I have changed the plugs with no effect. I have disconnected the the injectors and COP on each cylinder at idle with no real result. I have listened to each injector with a stethoscope and they are opening like they are supposed to. One may be clogged, but I'm leaning to the COP. I may buy a new one tomorrow and replace one at a time and see what happens.... Any suggestions?
06-26-2009, 07:12 AM
#5
Resident Ford Troll
Join Date: Jul 2006
Location: Delaware
Posts: 6,717
Sometimes the PCM will skip over a few miss fires, but also it can miss and throw codes just no SES light. Have it scanned anyway and see what it gives you. Also, with no codes its going to be hard to pinpoint a missfire. Easiest way (but not cheapest) is to take it to a shop and have the 'powerbalance' checked with a scanner. That wll tell you which cylinder is missing the fastest way
06-26-2009, 02:03 PM
#8
Thread Starter
Join Date: Jun 2009
Location: CA
Posts: 4
Problem is solved! Got a new COP this morning and started swapping out one at a time. Before I did that, I checked the resistance with a ohm meter on both the new COP and the original ones. They read out pretty comprable. I put the new COP in and took it out for a short run. Same problem. Got it back in the garage and pulled the new one and replaced it with the original. Went to the #1 next and remembering the old issue with coils breaking down after they get hot, I read out #1 against the same new COP I had just taken out.......... Surprise! #1 now read out with a higher resistance but the new one was at the same baseline. Replaced #1 with the new COP and it is running great! Thanks for all your suggestions.
06-26-2009, 02:12 PM
#9
5th Gear Member
Join Date: Mar 2008
Location: Ohio
Posts: 2,994
Problem is solved! Got a new COP this morning and started swapping out one at a time. Before I did that, I checked the resistance with a ohm meter on both the new COP and the original ones. They read out pretty comprable. I put the new COP in and took it out for a short run. Same problem. Got it back in the garage and pulled the new one and replaced it with the original. Went to the #1 next and remembering the old issue with coils breaking down after they get hot, I read out #1 against the same new COP I had just taken out.......... Surprise! #1 now read out with a higher resistance but the new one was at the same baseline. Replaced #1 with the new COP and it is running great! Thanks for all your suggestions.
Excellent!!
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