I have a 3800 sc that has shudder in the engine when I push the throttle hard and fast, but if I push it a medium fast steady push it revs up smooth with no shudder any help would appreciated.

I had the same issue. Replaced the trans mounts with 1" lowering mounts and the problem disappeared. If you have the stock mounts the driver side will sit too high and the drive angle will be too high.

Sorry I should have been clearer on discription this happens while in park so I'm sure it had something to do with engine. Thanks for reply

Would you say this "shudder" is a hesitation of the engine to accelerate if you "mash the gas"; or is the engine just acting like it is cutting out completely and then turning back on?

Does this shudder occur at a certain RPM point every time? (if so, what rpm?)

Other questions:
1) What transmission are you using?
2) Any aftermarket performance mods or bone stock?
3) What year PCM are you using and who custom tuned it (or is it stock)?

-ryan

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[This message has been edited by Darth Fiero (edited 11-06-2013).]

The PCM is from a 1998 Gtp has not been programmed engine is stock I believe tranny is 4t65e. The happens when you mash throttle all the way to the floor all at once. Doesn't do it when you push gas at a moderate rate,could this be a fuel issue when I checked with gauge it was about 42-45 at idle