4.8 2500 GM Idle/Acceleration Problems

[psychowardkevin]

Hello and greetings. Got a new problem with my 2006 2500 4.8L Van. Just had the Plugs changed and about a week after that noticed that it runs poorly when idling. Engine kicks every 2 or 3 seconds. Also in concert with that problem it is sluggish like it wants to stall when accelerating from a stop until about 5 mph when the rpm is higher. Seems to run fine above 10 mph. No check engine light either. What might be the problem? Thanks for the help.

[MT-2500]

What is the mileage on it?
What brand and what plug no did you feed it?
Does it have a dead miss or just rough running?
Any blinking check engine light when driving?

[DFBonnett]

First guess would be a plug wire, since the plugs are new.

[psychowardkevin]

To answer some questions. Looks like I had Iridium plugs put in. Odom at about 107000 now. No engine light at all blinking or otherwise and doesn’t feel like its missing hard just when accelerating feels like I’m driving a manual transmission and am giving it just enough gas not to die but not enough to run smoothly until 7 mph or so. I have since noticed that it runs rougher after a long stretch of highway driving and then stopping at a light. Ahh its like siting at a stop light with a manual transmission and u are feathering the clutch until it feels like you’re just about to kill the engine and then you let off the clutch and do that all over again never killing the engine.

[MT-2500]

You may have to get engine scanner on it and look things over.
Check for good hot blue spark to all plugs and see if any cylinders are missing.
Also pull vacuum hose off of fuel pressure regulator and look for gas in vacuum line. And for any sensors or wires or hoses that could have been left unplugged or knocked off.
Was it doing it before spark plugs changed?
Good Luck and let us know how it goes.
MT