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      04-23-2020, 01:23 PM   #1
Likeanowl
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Spark plugs. Two questions, one thread.

First question is my car on cold starts is SUPER jerky. It almost feels like I’m very lightly tapping the throttle repeatedly for the first 10 minutes of driving. Even with my foot steady on the gas it’s a pretty consistent jerk non stop while I’m on the throttle, once I let off it goes away though. I’m 100% this is not the standard DCT jerk... I’m familiar with that as well and this is different. Also when I first start it and go to back out of my driveway on a cold start it’s the worst. HUGE random jerks as I’m backing up almost like I’m slamming the gas and then the brake back and forth but it happens without ever touching the brake. Once it’s warmed up all these symptoms go away. Sound like spark plugs or something else? Elaborate please.

Second question which has been discussed in many different ways but I never saw a clear answer is if I get my plugs done at the dealership, can I buy the OEM Bosch plugs and gap them to run an e30 blend or should I only get the NGK’s for an e30 blend? People say the NGK’s cause misfires and I’m not trying to have that. Has anybody gapped the OEM plugs for e30 use? If so what results have you seen? If I do end up gapping which ever plugs I buy do I then HAVE to run some blend of ethanol all the time then or can I still run full tanks of 93 whenever I want. Much appreciated my friends.
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      04-23-2020, 01:41 PM   #2
behindthen0thing
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how many miles are on the car,
have you replaced spark plugs before.
are you running aftermarket intakes
are you tuned
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      04-23-2020, 04:21 PM   #3
Likeanowl
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36k miles
Not yet
Yes but I checked the sensors and they’re seated all
The way down
Only jb4 so far
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      04-23-2020, 06:18 PM   #4
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When I was on stock plugs I never experienced any of those issues. However when I upgraded to the NGK plugs and gapped them for the E30 tune and a future E85 tune I get that same jerkiness when backing out on cold starts. I learned that if I let the car sit for like 20 seconds and then give the throttle 3-5 good blips I won't get that jerk when I back out
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      04-24-2020, 04:07 AM   #5
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Quote:
Originally Posted by Likeanowl View Post
36k miles
Not yet
Yes but I checked the sensors and they’re seated all
The way down
Only jb4 so far
Yeah so the Jerky idle When cold seems to be very common with aftermarket instakes. Mine does this as well.
The only thing thats odd is that you're saying it lasts ten minutes. in my case it lasts about 30 seconds.
Your spark plugs are due, and it might help so you might as well get them changed and see what happens.

Try putting your JB4 on map zero before you start also and see if that makes any difference, or just disconnect it from the OBD port.
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      04-24-2020, 03:18 PM   #6
Likeanowl
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Seems to still happen even at map 0.

Regarding the intakes, do you suggest trying to clean the sensor maybe? If so, clean it how/with what?
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