2004 car: Bucking at low throttle positions???

TexasViper35 · Mar 6, 2018

I had put some Techron in the tank and soon had a misfire on cylinder 4. Changed out all of the plugs and everything was great!

Now about 300 miles later the car was ‘bucking’ every time I up shifted and slowly rolled on the throttle. It was driving me nuts and I questioned whether or not I was causing it with my foot input on the throttle. Sure enough the next day cylinder 4 is misfiring again, changed it and no issues, for a day, but now she’s bucking again! I guess I’ll be putting a new spark plug in #4 soon.

Any ideas about what is causing this?

Steve-Indy · Mar 6, 2018

May be time to look at coils/wires.

MoparMap · Mar 8, 2018

Since it seems to be isolated to a specific cylinder I would tend to agree with Steve. Sounds like the plug is getting fouled, so would guess the wire is either cracked and leaking voltage or the coil is going out. You could check all the other little sensors too like the TPS, intake temp, O2, etc. as those can make a car run kinda rough when they get weird, but the single cylinder thing would tend to make it seem like an ignition or injector issue. I suppose it's possible the injector could be leaking fuel and not closing causing that cylinder to run rich and foul the plug too.

TexasViper35 · Apr 25, 2018

MoparMap said:
Since it seems to be isolated to a specific cylinder I would tend to agree with Steve. Sounds like the plug is getting fouled, so would guess the wire is either cracked and leaking voltage or the coil is going out. You could check all the other little sensors too like the TPS, intake temp, O2, etc. as those can make a car run kinda rough when they get weird, but the single cylinder thing would tend to make it seem like an ignition or injector issue. I suppose it's possible the injector could be leaking fuel and not closing causing that cylinder to run rich and foul the plug too.

The #4 wire was cracked, inside. I had a new set of wires installed and man what a difference!!! It’s easy to forget that original feel of the car over years of time, but it’s back. 14 year old plug wires are just not a good idea to run on.

Thanks to both of you for the advice.

MoparMap · Apr 26, 2018

Glad you got it back running strong! When I put my headers on a few years back I ended up messing up some of my wires. They had enough miles and age on them that they just didn't like coming off. The silicone ends had basically fused to the plugs, so a new set was in order.

2004 car: Bucking at low throttle positions???

TexasViper35

Enthusiast

Steve-Indy

VCA Venom Member

MoparMap

VCA National President

TexasViper35

Enthusiast

MoparMap

VCA National President

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