1992 GMC Yukon Missing/backfiring at Highway speed
May 15th, 2014, 8:42 AM
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1992 GMC Yukon Missing/backfiring at Highway speed
Hello,
I have a 1992 GMC Yukon, 5.7 350, 4WD, no cat 234,0000 miles on it. About a year ago, it started mssing at highway speeds. Changed plugs, cap, rotor, wires and it cleared up. The missing has come back, replaced everything again but it is still missing at highway speeds and it sounds like it is backfiring through exhaust. Let a local shop look at it for 3 days and they could not figure it out.
-It only misses at higher speeds especially under load
-If you let off accelerator when it starts to miss, it will clear up
-Also, when you let off accelerator while driving the RPMs lope up and down
-Drives alright at lower speed, just running rough/lacking power once truck heats up
I also went ahead and swapped ignition coil, and there are no codes being thrown. Thank you in advance for any suggestions.
I have a 1992 GMC Yukon, 5.7 350, 4WD, no cat 234,0000 miles on it. About a year ago, it started mssing at highway speeds. Changed plugs, cap, rotor, wires and it cleared up. The missing has come back, replaced everything again but it is still missing at highway speeds and it sounds like it is backfiring through exhaust. Let a local shop look at it for 3 days and they could not figure it out.
-It only misses at higher speeds especially under load
-If you let off accelerator when it starts to miss, it will clear up
-Also, when you let off accelerator while driving the RPMs lope up and down
-Drives alright at lower speed, just running rough/lacking power once truck heats up
I also went ahead and swapped ignition coil, and there are no codes being thrown. Thank you in advance for any suggestions.
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greatwhite99
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August 27th, 2011 4:00 PM
