Spark plug wires coming off while driving?

beetle · October 26, 2015

Happened once...wire came off the coil, not the plug. Rubber boots not tight enough, I expect this to continue.

Brianx220 · April 21, 2016

Yes! Its good to find out it's not just my truck doing this. It happened twice to me already. First time I took it to Chevy and they told me it had just come loose and they replaced the wire. The second time was a different cylinder that the plug came loose. This time I did not have the time nor was there a dealer open due to flooding. I just plugged it back in and the truck ran smooth but the T/C was still engaged and the truck was not coming to a stop properly. Next morning it was as if nothing happend so the dealer said they could not find any codes and it is running properly..... This really angers me because now I seem like the dumb one telling them there's a problem, with pictures and a video in hand.

14WhiteZ71 · April 22, 2016

Happened to me 3 times. 1st time I was luckily close by my dealership, they replaced with a new one (different color wire and all). 2nd time I was 20-25 minutes away (replaced this one as well). Was angry at this point as it was. 3rd time I was pulling a 20' trailer with some playground equipment from over an hour away. Dealership ended up replacing all remaining wires for me and haven't had a problem since. They said they'd never seen it on my 1st two trips. 3rd trip they said they had seen about 5 or 6 more in the last few months. All is well now.

SouthernSilveradoGuy85 · April 22, 2016

This is honestly the first time hearing of this. I've had my '14 for right at 2 years and 24,000 miles and never had this happen. I've done a few things that would help the issue if it were to happen so maybe I got a little lucky or some of you are unlucky lol. The is my first truck/vehicle with ignition coils, my last 2 Chevys had the distributor. At least my '98 had it so you put the in order on each side and they didn't cross all around like my '86. So the '98 was easy when changing the wires, or should say easier.

For future reference, how or where do the plastic covers come off. I've tried pulling them lightly off but don't want to break any tabs or anything.

decee · April 22, 2016

sorry, spark plug wires. not the plugs unless someone was tampering with them! The dealership said they have found it to be a problem with a select few models and are hoping GM issues a recall and replaces. they check and tighten all of them when I go in. I live in rural Ontario so dirt roads are what i mainly use. But when the engine light flashes and traction control comes on and Onstar tells you to go to the dealership...

What engine?

HammerofDawn92 · April 28, 2016

Had the same issue with my 2014 Silverado. Twice now the plug wire has come loose. Mine did not throw a check engine light or traction control light. Last night on the way home in rush hour it started chugin' and idling rough. I am down in Atlanta, its pretty rare to find a dirt road. I-20, or I-285 are a little rough but nothing like the roads up north! Got home, and popped the hood to find the awesome knocking from the passenger side. Saw that cylinder 4 plug wire just chillin with the exhaust manifold!

Glad I am not the only one seeing this. I am calling Carl Black Chevrolet in Kennesaw to see if they can push GM about it. Its annoying more than anything!

kapediego · May 17, 2016

I have a 2014 GMC Sierra SLT with 13k miles and was experiencing a ticking sound for well over a month. I did not have any roughness issues and the check engine light never came on, so I originally thought it was the belt system. I checked last night and the spark plug wire on the passenger side closest to the firewall had worked loose. I moved the wire away from the plug (very easily) and the ticking stopped, but the engine began to run very rough. Once I put the wire back on, the engine was fine and no ticking, so it looks like the noise was arcing between the wire and the plug. The spark plug wire is now very corroded, so its going back to the dealer to be replaced. This is the second time a spark plug wire came off on my truck. The first time the check engine light came on and the engine ran very rough. I don't drive on rough roads, so bumps would not have caused the wire to come lose in my case.

tnchevy · May 17, 2016

I am going to pop the hood on mine when I get home and check my plug wires after reading this.

GMCustomerService · May 20, 2016

I have a 2014 GMC Sierra SLT with 13k miles and was experiencing a ticking sound for well over a month. I did not have any roughness issues and the check engine light never came on, so I originally thought it was the belt system. I checked last night and the spark plug wire on the passenger side closest to the firewall had worked loose. I moved the wire away from the plug (very easily) and the ticking stopped, but the engine began to run very rough. Once I put the wire back on, the engine was fine and no ticking, so it looks like the noise was arcing between the wire and the plug. The spark plug wire is now very corroded, so its going back to the dealer to be replaced. This is the second time a spark plug wire came off on my truck. The first time the check engine light came on and the engine ran very rough. I don't drive on rough roads, so bumps would not have caused the wire to come lose in my case.

Hi kapediego,

I’m sorry to hear that cause of the ticking noise has resulted in a corroded spark plug wire. I see you’ve mentioned visiting the dealer to get the wire replaced, have you been able to contact them yet? If you would like me to facilitate in setting up an appointment, please feel free to send a private message my way.

Have a great day.

Julianne M.

GM Customer Care

Andy Seibel · October 3, 2016

My truck just gave me a PO307 code this weekend. Misfire on cylinder 7. I dropped the truck off at dealership yesterday. I wish I would have read this post first, maybe I could have just fixed it myself. I'll see if they come up with a loose plug wire.

The funniest thing was I noticed the rough/ vibrating engine a few times in the past week, but only on Saturday morning did it finally light up the "check engine" light.

Did anyone have any other problems after driving with one cylinder out? I read somewhere that it can cause issues with the cat. Once the engine light went on, I probably drove about 20 miles to get to the dealer.

2doorpost · October 6, 2016

Just went through this on my 2015 Silverado at 5300 miles. Loose connection at the coil pack. Truck stalled out 4 times and finally went in to limp mode. Blinking check engine light drove 1/4 mile to home.........Flatbed into dealer for the fix

Same thing on my 2014 Silverado at 2300 miles. Loose wire at the spark plug. Threw a steady check engine light. Drove to dealer 50 miles.

Edited October 6, 2016 by 2doorpost

quail hound · October 6, 2016

Maybe it's my commercial driver ocd but I occasionally check things like plugs and wires (there's no plugs on a rig but we go over everything before each trip). Start the truck and touch each wire, you'll feel a bit of a tick if a plug wire is coming loose or a plug is backing out. My '05 will back out the number one plug periodically, haven't seen any problem with my '15 and I do a lot of driving on washboard dirt roads and forestry roads. Pop those hoods every now and then folks!

Andy Seibel · October 6, 2016

I'll see if they come up with a loose plug wire.

Update: Yes, it was a loose plug wire. They replaced it. No issues driving home, I haven't gone far since then.

MikeNH · October 6, 2016

Maybe it's my commercial driver ocd but I occasionally check things like plugs and wires (there's no plugs on a rig but we go over everything before each trip). Start the truck and touch each wire, you'll feel a bit of a tick if a plug wire is coming loose or a plug is backing out. My '05 will back out the number one plug periodically, haven't seen any problem with my '15 and I do a lot of driving on washboard dirt roads and forestry roads. Pop those hoods every now and then folks!

I wouldn't touch a plug wire on a running engine. If there's anything wrong with the wire, you're gonna get hit with like 50k volts. It hurts. A lot. haha

quail hound · October 6, 2016

I wouldn't touch a plug wire on a running engine. If there's anything wrong with the wire, you're gonna get hit with like 50k volts. It hurts. A lot. haha

Yeah it does hurt but it will never happen unless your wire is damaged and you can see it arcing, just use some common sense. You've never adjusted the timing on a running engine before?