LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

throttle hesitation and backfire

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Old Nov 4, 2008 | 03:58 PM
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x24-7x's Avatar
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throttle hesitation and backfire

Problem started 2 days ago. It doesnt do it all of the time, but sometimes under decently heavy acceleration my car will hesitate and occasionally backfire. It hasnt done it yet today. But this mornin it cranked forever before it finally started. I discovered yesterday one of my plug wires had a tear in it, but only through the rubber shell and you couldnt see any wires or anything. And if this was the problem..wouldnt it do it all of the time? Also the car hasnt been tuned and my o2's are shot im pretty sure. Which will be replaced soon. But the car ran decent with all of that wrong..so im thinkin it could be the wire..any other ideas??
Old Nov 4, 2008 | 06:00 PM
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Does the car have to warm up before it starts to hesitate? If so, I'd definitely start with O2s
Old Nov 5, 2008 | 11:03 AM
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it seems to do it in both loops. normally though i let it warm up before i drive it because when it first starts for the day..it runs terrible if i dont wait
Old Nov 5, 2008 | 03:12 PM
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Wires

First pull all wires or check wires for cracks. Second pull plug wires and check plugs I would check plugs for looseness, then I would pull plugs one by one and check to see if there white, If thats the case its time for new o2s if your getting no codes it will get worse later..
Old Nov 5, 2008 | 06:05 PM
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new wires..plugs were pulled a few weeks ago..actually they were pulled about 4 times in 3 days..lol. but it seems like that wire could be the problem?? any other ideas?
Old Nov 6, 2008 | 02:22 AM
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no

try that see what it is check plugs also for lean condition pull them see what they look like send me pics ramair972003@yahoo.com
Old Nov 7, 2008 | 12:56 PM
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x24-7x's Avatar
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getting new wire today so ill be checking it
Old Nov 7, 2008 | 05:59 PM
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also. when the motor hasnt been warmed up and running for a while..it takes unusually long to start. i replaced the wire, that didnt fix my problem. im low on funds at the moment so any ideas?
Old Nov 7, 2008 | 10:46 PM
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i had about the same problem awhile back, when it got hot (around 210) it would start choppin, turned out i had a few bad plug wires. got new wires and plugs and ran perfect
Old Nov 8, 2008 | 12:24 AM
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sounds like its not spraying enough fuel to start it in the mornings. after a while its getting the air to fuel mixture right to get it to light. but it would most likely be bad plug wires causing miss fires. that would explain backfires and hesitation.
Old Nov 8, 2008 | 12:51 PM
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plug wires appear to be fine. and it only misses at higher rpms and every once in awhile it doesnt even do it..?? any other ideas??
Old Nov 8, 2008 | 02:43 PM
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Originally Posted by x24-7x
...... I discovered yesterday one of my plug wires had a tear in it, but only through the rubber shell and you couldnt see any wires or anything. And if this was the problem..wouldnt it do it all of the time? ....
Originally Posted by x24-7x
plug wires appear to be fine. and it only misses at higher rpms and every once in awhile it doesnt even do it..?? any other ideas??
If the plug wire insulation has a "tear" in it, its not "fine". That destroys the insulating value of the covering. You're trying to contain 20-30,000 Volts. A tiny crack of tear will have the spark arcing between wires (would explain the backfire) or to the nearest metal surface. It's going to be worse on a cold, damp day, when there's moisture in the air and condensing out on the cold engine parts. Gonna arc like crazy.

Last edited by Injuneer; Nov 8, 2008 at 02:52 PM.
Old Nov 9, 2008 | 12:55 PM
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i replaced the bad plug wire..sorry. must have forgot to say that
Old Nov 13, 2008 | 10:12 AM
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ok so i was able to get my codes read. it said both of my o2 sensors were leaning out. so im going to be replacing those today along with my fuel filter.
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