Drummer Posted March 22, 2010 Report Share Posted March 22, 2010 Well after this whole winter of my car acting up with it missing every now and then while driving it finally started to get worse. Not sure if it's a coil or wire or plug but it only misses while I'm driving in the lower but sometimes occurs in the higher rpms. Finally yesterday the ses light came on and i quickly check it to see what cylinder is missing and it's the # 5 cylinder. Also driving in the rain it didn't miss that much, but when it was in the upper 60s and sunny it was missing a lot more than in wet weather which kinda confused me. I'm thinking it could either be a coil or a wire but not sure. The wires aren't even a year old and I've got AC Delco platinum plugs in although original when i bought the car. What would you think it could be? Quote Link to comment Share on other sites More sharing options...
douellette Posted March 22, 2010 Report Share Posted March 22, 2010 Well after this whole winter of my car acting up with it missing every now and then while driving it finally started to get worse. Not sure if it's a coil or wire or plug but it only misses while I'm driving in the lower but sometimes occurs in the higher rpms. Finally yesterday the ses light came on and i quickly check it to see what cylinder is missing and it's the # 5 cylinder. Also driving in the rain it didn't miss that much, but when it was in the upper 60s and sunny it was missing a lot more than in wet weather which kinda confused me. I'm thinking it could either be a coil or a wire but not sure. The wires aren't even a year old and I've got AC Delco platinum plugs in although original when i bought the car. What would you think it could be? maybe injector starting to go bad? Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted March 22, 2010 Report Share Posted March 22, 2010 I'd bet either bad injector, or bad lower intake manifold gasket, allowing extra air in at #5. Not as likely to be a coil, since it's a batch fire setup, and I'd expect 2 misfires, since each coil fires two cylinders. A bad plug wire would do what you describe, though. Quote Link to comment Share on other sites More sharing options...
Euro Posted March 22, 2010 Report Share Posted March 22, 2010 I'd start with the plug or wire and see if that helps ya out! Quote Link to comment Share on other sites More sharing options...
jman093 Posted March 23, 2010 Report Share Posted March 23, 2010 The upper intake manifold might be getting real bad. Vacuum or coolant leak into the cylinder. Quote Link to comment Share on other sites More sharing options...
Drummer Posted March 23, 2010 Author Report Share Posted March 23, 2010 guess I'll start with the plug and wire and coil then injector see what happens, and hope it's not the intake. Quote Link to comment Share on other sites More sharing options...
AL Posted March 23, 2010 Report Share Posted March 23, 2010 Do you still have the metal heat shields installed on the plug wire? If so, then get rid of them... My misfire was caused by them and so were a couple other peoples Quote Link to comment Share on other sites More sharing options...
Drummer Posted March 23, 2010 Author Report Share Posted March 23, 2010 Do you still have the metal heat shields installed on the plug wire? If so, then get rid of them... My misfire was caused by them and so were a couple other peoples We have a winner. I took those things off a while back but was worried about the wire so I put them back on but I guess their coming off again Why do those protectors do that anyways? Quote Link to comment Share on other sites More sharing options...
AL Posted March 23, 2010 Report Share Posted March 23, 2010 I believe they ground out some how... I am not sure exactly how tho... Shawn E might know, He came up with the idea when mine was misfiring Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted March 24, 2010 Report Share Posted March 24, 2010 The reason they do that is simple. Electricity ALWAYS takes the easiest path. If your boots are surrounded by metal shields that provide a good path to ground, ANY imperfection that allows current leakage from the wire or the boot in the vicinity of the shields will result in you spark going to ground, rather than to the plug. At that point, you're faced with two choices....buy new plug wires, or remove the grounding problem. I understand what GM was trying to do with those shields, they were trying to protect the boots from excess heat...but metal surrounding the plug wire was a very poor choice. Do you still have the metal heat shields installed on the plug wire? If so, then get rid of them... My misfire was caused by them and so were a couple other peoples We have a winner. I took those things off a while back but was worried about the wire so I put them back on but I guess their coming off again Why do those protectors do that anyways? Quote Link to comment Share on other sites More sharing options...
carkhz316 Posted March 24, 2010 Report Share Posted March 24, 2010 The reason they do that is simple. Electricity ALWAYS takes the easiest path. If your boots are surrounded by metal shields that provide a good path to ground, ANY imperfection that allows current leakage from the wire or the boot in the vicinity of the shields will result in you spark going to ground, rather than to the plug. At that point, you're faced with two choices....buy new plug wires, or remove the grounding problem. I understand what GM was trying to do with those shields, they were trying to protect the boots from excess heat...but metal surrounding the plug wire was a very poor choice. Why wouldn't you just get new plug wires as faulty ones are just going to get worse and make problems? And what about the whole metal engine block that would otherwise surround the plug wires???? I still have them on my 98 and only have one plug wire set replacement since I've had it, so 30K+ miles and not so much as a single problem with the metal heat shields. Quote Link to comment Share on other sites More sharing options...
SS-Jon Posted March 25, 2010 Report Share Posted March 25, 2010 Did you fix it yet? Since you have access to a scan tool can you watch data and missfire counts? It should show most of the missfires on #5 but it could show a bunch on the mated cylinder if its a bad coil. How many miles are on the plugs and wires? Quote Link to comment Share on other sites More sharing options...
Drummer Posted March 25, 2010 Author Report Share Posted March 25, 2010 it's probably the crappy autozone plug wires, but removing the heat shields worked so it's ok till I can find a good pair at a junkyard Quote Link to comment Share on other sites More sharing options...
Galaxie500XL Posted March 25, 2010 Report Share Posted March 25, 2010 My money's on the Autozone wires. I had two Buick V6 cars I put those wires on at about the same time. 4 months later, I was throwing away those wires on BOTH cars, due to misfires. it's probably the crappy autozone plug wires, but removing the heat shields worked so it's ok till I can find a good pair at a junkyard Quote Link to comment Share on other sites More sharing options...
carkhz316 Posted March 25, 2010 Report Share Posted March 25, 2010 it's probably the crappy autozone plug wires, but removing the heat shields worked so it's ok till I can find a good pair at a junkyard Are you talking about good JY heat shields or plug wires? You would be wasting your time with JY wires. The heat shields on the other hand, if they are indeed bad, I wouldn't replace them, despite my post about them being problem free on mine. Quote Link to comment Share on other sites More sharing options...
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