Slight drop in RPM when just touching throttle

[CaptainXL]

Does anyone know what the cause is for this slight drop in RPM at idle just after barely pressing the throttle?

[video]https://www.youtube.com/watch?v=bwZnLth73Fs[/video]

 

[Mounce]

Didn't watch the video but, that's been asked here many times. Seems like 80% of us have the issue (including myself) and if I remember correctly, it's been ruled as normal. Of course, you could try a tune up (plugs, fuel filter, intake filter, throttle body cleaning and such) and see if that takes it away though, but it'll probably still happen.

 

[CaptainXL]

My first instinct is that this is stumble. More likely due to a vacuum leak. My scan tool data shows enrichment at idle. I guess what I am hoping for is a reply from someone to verify this. Anyone notice this stumble disappear after fixing an intake manifold leak?

 

[BlazingTrails]

What's the vacuum reading at idle? Have you cleaned the throttle body recently?

 

[Mike w]

Mine does the same..

 

[SmokeyMcBlazer]

mine does that also.

 

[CaptainXL]

So everyone's engine does this? Reason I ask is because sometimes I can catch it not doing it.

 

[IllogicTC]

It seems at least semi-normal to me, also. As a precautionary measure, when's the last time your throttle body was cleaned?

 

[CaptainXL]

The last time? About 5k ago when I installed a new throttle body gasket.

 

[mcsteven]

Mine does it too.

 

[KNBlazer]

mine has done it for years, and now as well with a recently rebuilt engine...

I have requested that those with a PCM tune chime in, but no one yet has come forward...

 

[The Neens]

mine has done it for years, and now as well with a recently rebuilt engine...

I have requested that those with a PCM tune chime in, but no one yet has come forward...

Mine does it with or without custom tune installed...Throttle body is spotless...

 

[KNBlazer]

Mine does it with or without custom tune installed...Throttle body is spotless...

TM intact or modified?

 

[The Neens]

TM intact or modified?

Modified...Hmmmmmm, never thought of that...Thanks...I'll have time to play with it next weekend...

 

[The Neens]

TM intact or modified?

Reflashed with stock Torque Management, still does it...

 

[CaptainXL]

I just go done replacing the intake manifold gaskets this past weekend. Trying to track down a loss in performance.

I recently switched gas and noticed a big improvement in mileage and power. I am pretty sure half of the equation just got solved.

Still unsure if the rpm drop is still there or not.