Engine Surge While Driving?

[bassadict69]

I have a 2002 Silverado 4x4 with a 4.8L, when driving sometimes my rpms will surge about 200 rpms. I have noticed it doing it mostly in the mornings but even after it reaches normal temperature. I also noticed if I am driving at a steady speed & let off the throttle just a small hair, the rpms will surge.

 

Any ideas what the problem is?

 

It runs perfectly other than that little annoying thing!

[bassadict69]

Anyone?

 

Noone has heard of this before?

[Draenor]

is the trans an auto or manual?

Auto-could be the TC locking and unlocking. Dunno

[bassadict69]

Tranny is auto...Is that normal for the TC to cause a surge in rpm when locking & unlocking?

[98 Z71 SLT]

Always start with the basics. Test your fuel pressure. Check for a leaking fuel pressure regulator. Install a scan tool, making sure you have no SES codes in history. How is the engine's state of tune?? How are the filters?

 

I'm gonna take a longshot on this one...but I'm gonna say that your throttle body is full of carbon, causing your gas pedal to stick at times. I would remove the TB and totally clean the carbon out of it, then take it for a spin.

 

And, if cleaning the TB doesn't help you...I would then take off the EGR calve and clean that out also.

 

Post up what you did to fix this...

[bassadict69]

I will have to get the f/p tested...no codes a few months ago (being doing the surgine for over a year), state of tune? I assume you mean plus, wires, etc...plugs changed two weeks ago, still original wires, fuel filter changed last year...new stock air filter, oil changes done regularly. MAF cleaned this weekend...still surges!

 

Cleaning the TB? Is this a big job? Should I pay to have that done? I am lost on this one & have no experience with TB's.