Shudder when I give the engine power

[vukos]

I have owned this one-owner 99 limited for about a year now. I have this issue that has persisted the whole time. Sometimes the effect is very faint and other times very strong.

Whenever I touch the pedal to accelerate (when already in motion), I feel a short shudder and then acceleration resumes normally. Likewise, whenever I let go of the pedal to stop accelerating, I also feel this shudder again. The best way I can describe it is that the effect is binary, like turning something on and off: Shudder when on and shudder when off, for example.

When I accelerate very lightly, the effect is diminished. Likewise the effect is stronger if I wear my lead foot.

I think the effect is coming from in front if me, as if the engine performs a short shudder when power is applied and shudders when power is removed.

I haven't noticed any other issues. Any ideas?

 

[zcruiser]

Have you changed the plugs?

 

[Brute1100]

Clean mass air flow sensor...

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[vukos]

Spark plugs are new as of 10k miles and I cleaned the MAF sensor last month

 

[ladywolf]

it almost sounds as if it's a fuel issue. Check to see if your injectors/and/or filter arent gummed/stopped up.

 

[papapoopski]

I recently experienced similar symptoms.

Do you notice it happening more when it's wet/raining?

My issue would usually work itself out, then one day I stomped on the gas while it was doing the shudder. Dashboard lit up with lights, check engine light came on blinking.

Read the code (I forget the number), cylinder misfire. I changed 2 ignition coils, problem solved. Took 10 minutes, very easy to do. Runs perfect now.

 

[zcruiser]

Spark plugs are new as of 10k miles and I cleaned the MAF sensor last month

Don't take this as I don't think you know what you're doing, but (a) did you install dual-electrode plugs and (b) the MAF can be tricky to clean as there is a part that is visible that can be easily cleaned and there's the actual wire that is what really needs to be cleaned that is deeper in the MAF.

For me, I knew my MAF needed a deep-clean when it took more than 2-3 seconds to start. Never attributed that to shudder but I guess it's possible.

 

[octanejunkie]

...one day I stomped on the gas while it was doing the shudder. Dashboard lit up with lights, check engine light came on blinking.

Read the code (I forget the number), cylinder misfire. I changed 2 ignition coils, problem solved. Took 10 minutes, very easy to do. Runs perfect now.

I had the same experience

In troubleshooting, I changed the plugs, wires, fuel filter, air filter, cleaned MAF ended up being a bad coil.

All the other stuff didn't hurt to do, but cylinder specific misfires usually lead to either a coil or injector, depending on the other codes that appear.

 

[jgue467]

...

I think the effect is coming from in front if me, as if the engine performs a short shudder when power is applied and shudders when power is removed.

I haven't noticed any other issues. Any ideas?

Does the CEL light blink when this shuddering takes place? If it does blink, it is telling you to let off the throttle, too much unburnt fuel is making it back to the exhaust sensors possibly damaging them.

Any stored or pending CEL codes? If you don't have a reader, take it to autozone or other auto parts store, they'll read it for free. Luck. :cowboy:

 

[vukos]

Does the CEL light blink when this shuddering takes place? If it does blink, it is telling you to let off the throttle, too much unburnt fuel is making it back to the exhaust sensors possibly damaging them.

Any stored or pending CEL codes? If you don't have a reader, take it to autozone or other auto parts store, they'll read it for free. Luck. :cowboy:

I have a CEL for a leak somewhere in the emissions system, but this problem existed for about six months before that code and the CEL never turned on briefly when this happens.

It really is a binary affect that triggers the moment I give the engine gas. Once the gas is on, I can accelerate harder and acceleration stays smooth. If I let go of the accelerator suddenly, I feel the shudder again

 

[zcruiser]

That’s not ignition then. Maybe a bearing?