Rough idle

[applianceguy]

My 98 astro 150,000 miles auto has started Idling rough. If I turn a/c off nothing changes. If I drop it in netural she smoothes right out. If I give it just a gas a touch it smoothes out. No Codes showing. New fue l pump, did it before pump. Need a clue were to start. Runs and drives great.

Thanks

[astroturf]

Have you checked for vacuum leaks, and also inspected/cleaned out your EGR Valve?

Try those things.

I am sure others will chime in also.

Good Luck, Jim

[Cobra]

vacuum leak is a good start, i've heard cleaning you MAF can also help i've done mine it was pretty dirty and showed some minor signs of improvement after. i'd also check my cap and rotor for corrosion, i know lifted spent quiet a while chasing a lumpy idle but for the lift of me i can't remember what the cause was.....

edit: when you say rough how rough do you mean like wanting to stall rough or just enough to feel it

[applianceguy]

Today.........cut exhaust to adjust the Cat........found it hollow gone. Put anti-flowler on O2 sensor, no more 420 code. No codes at all

Cleaned MAF sensor with correct cleaner and put on a new air filter

Checked all vacuum lines.......already replaces all of them

Cap Rotor wires and plugs 15,000 ago

Run Great, Does not stall, just idles real bad. Drop into N or touch gas and smoothes out

Will pull EGR tomorro and clean it.

Is there an idle idle adjustment screw/?????????????????

Thanks
Mike

[1Gary]

Mike-suggest you go to your local parts store and buy from the help section a EGR replacement screen gasket to prevent carbon from getting into it.

[applianceguy]

Mike-suggest you go to your local parts store and buy from the help section a EGR replacement screen gasket to prevent carbon from getting into it.

I'll try anything once............OK

[astroturf]

No idle adjust screw.

Have you cleaned/inspected throttle body?

Jim

[applianceguy]

No idle adjust screw.

Have you cleaned/inspected throttle body?

Jim

Yep........I was having a problem with carbon buildup around butterfly and sticking trottle. Hey do these trottle bodies wear out? Its got 150,000 miles

Mike

[astroturf]

With that said Mike, I think the EGR Valve is next on your list.

Jim

[applianceguy]

With that said Mike, I think the EGR Valve is next on your list.

Jim

Pull EGR valve anbd was nasty. Used oven cleaner to clean it, nasty nasty. That did the thick. On my last truck this would throw an engine code??

Mike

[astroturf]

Glad you got it worked out Mike.

Now you can enjoy your new found MPG increase.

Jim