Spark Plug Issue?
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Le Mans Master
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From: Lake Havasu City Arizona
Spark Plug Issue?
I had my dealership install new spark plugs. Now whenever under heavy acceleration when passing, etc. it starts to cut out and miss at higher RPMs. Not being a mechanic, I'm assuming one of the wires or plugs wasn't installed properly? Seems like too much of a coincidence that it was running perfectly before the plug replacements.
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Le Mans Master
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From: Lake Havasu City Arizona
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I had my dealership install new spark plugs. Now whenever under heavy acceleration when passing, etc. it starts to cut out and miss at higher RPMs. Not being a mechanic, I'm assuming one of the wires or plugs wasn't installed properly? Seems like too much of a coincidence that it was running perfectly before the plug replacements.
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At night, in a dark, and I mean dark, open the hood and look for flashes of light. It might be a cracked porcelin on a plug too.
You're looking for a loose connection on a plug or a coil.
Elmer
You're looking for a loose connection on a plug or a coil.
Elmer
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Melting Slicks
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Could be:
Incorrect plugs.
Defective plug(s).
Wrong gap(s).
Loose plug(s).
Loose plug wire(s).
Bad plug wire(s).
Any combination above.
I would take it back to where you had the work performed and let them fix it.
Incorrect plugs.
Defective plug(s).
Wrong gap(s).
Loose plug(s).
Loose plug wire(s).
Bad plug wire(s).
Any combination above.
I would take it back to where you had the work performed and let them fix it.
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Thread Starter
Le Mans Master
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From: Lake Havasu City Arizona
Thanks for all the replies. I'll will be taking it in 7:30 AM monday. I know the mechanic and have never had an issue with him. He'll feel worse about it than I do, but he's a fixer.
When I really notice it is when I get on it. When it starts into the yellow zone before shifting that is where you can really feel it. It's specifically like it's missing and shudders a bit. When I drive around normally with the car I don't notice a thing. Just to check a couple of other potential culprits I'm going to remove my range device that prevents the car from going into 4Cy mode and see if there might be a shudder going from 4 to 8 cylinders. You just never know. But I want to rule that out. I'm not a mechanic by any means. There's too many parts to remove before even getting close to removing the Spark plugs. I don't posses that particular skill set! We are all dumb in spots, and that is one of those spots for me.
When I really notice it is when I get on it. When it starts into the yellow zone before shifting that is where you can really feel it. It's specifically like it's missing and shudders a bit. When I drive around normally with the car I don't notice a thing. Just to check a couple of other potential culprits I'm going to remove my range device that prevents the car from going into 4Cy mode and see if there might be a shudder going from 4 to 8 cylinders. You just never know. But I want to rule that out. I'm not a mechanic by any means. There's too many parts to remove before even getting close to removing the Spark plugs. I don't posses that particular skill set! We are all dumb in spots, and that is one of those spots for me.
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Le Mans Master
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From: Lake Havasu City Arizona
Well after test driving the car to get more specific symptoms it seems it is not the spark plugs, but the torque converter. The symptoms match perfectly what is experienced with a failing torque converter. Mostly I feel the transmission slipping and vibration shuddering as it slips into the next higher gear. It revs up without actually accelerating as it slips into gear. The acceleration is a little rough.
I have had the torque tube replaced at 18,000 miles. I'm pretty sure it isn't the transmission. Having removed the Range device I couldn't detect any fluctuation in rpm as it went back and forth between V8 and 4cylenders. It has always shifted perfectly.
I have had the torque tube replaced at 18,000 miles. I'm pretty sure it isn't the transmission. Having removed the Range device I couldn't detect any fluctuation in rpm as it went back and forth between V8 and 4cylenders. It has always shifted perfectly.
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Well after test driving the car to get more specific symptoms it seems it is not the spark plugs, but the torque converter. The symptoms match perfectly what is experienced with a failing torque converter. Mostly I feel the transmission slipping and vibration shuddering as it slips into the next higher gear. It revs up without actually accelerating as it slips into gear. The acceleration is a little rough.
I have had the torque tube replaced at 18,000 miles. I'm pretty sure it isn't the transmission. Having removed the Range device I couldn't detect any fluctuation in rpm as it went back and forth between V8 and 4cylenders. It has always shifted perfectly.
I have had the torque tube replaced at 18,000 miles. I'm pretty sure it isn't the transmission. Having removed the Range device I couldn't detect any fluctuation in rpm as it went back and forth between V8 and 4cylenders. It has always shifted perfectly.
Bill
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Thread Starter
Le Mans Master
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From: Lake Havasu City Arizona
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Bill
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Le Mans Master
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From: Lake Havasu City Arizona
Again, I would let the mechanic figure that out. Just tell him the symptoms Vs your diagnosis. When you have a fever, headache, runny nose, and feel weak all over you don't walk in the doctor's office and say you have Covid since those symptoms apply to more than one disease. You let the doctor figure out what is wrong and follow their advice/counsel. At the beginning, you say you aren't a mechanic. Don't try to be one when you take the car to the dealer.
Bill
Bill
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This can get difficult. Based on codes and no CEL I would lean transmission. Otherwise, you would have detonation in a cylinder to cue you in on a bad plug/wire/coil pack. If a torque convert is failing, you will only notice it under high pressure usually. If you ease into the throttle till redline it should not shudder if the firing is correct. If you open the throttle up and you notice the rpms climbing but not progress you have different problems as noted.
Thread Starter
Le Mans Master
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From: Lake Havasu City Arizona
I made a mistake thinking it was the spark plugs. It is more than likely the torque converter or something else. I'm going over to them this morning and going to demonstrate the shuddering when winding it out before slipping into the next higher gear.When I first felt that was right after I got back from service and just "assumed" it had something to do with the spark plugs.
Unfortunately the car is 100 miles over the drive train warranty. So any repairs will be coming out of my own pocket.
I'll report back. This dealer service has been very good.
Burning Brakes
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From: Olathe KS
Your symptoms are exactly what mine were after my header install. It was a loose plug wire. Not loose enough to throw a code but had a major hesitation/shudder above 4k rpm at anything over half throttle, especially when in boost. Those plug wires up against the firewall, especially on the passenger side are a real PIA to get a hand on so it's pretty easy to not get them snapped all the way on. I'd have him take 10 minutes to give each wire a firm press to make sure they are seated correctly. There could be more than one that's loose too. If that doesn't fix it then move on to something else...