P1404 code 1999 suburban L31

[travis]

Final chapter in this Suburban saga

1999 suburban C2500, stock L31 Vortec 350. Idles “mostly” smooth at idle with just a faint touch of roughness. Runs normal and smooth at medium or heavier throttle, but at very light throttle acceleration or cruise, it bucks, misfires, burbles, etc...and it all clears up as soon as you give it more throttle. I’ve cleaned the EGR valve before...does it sound like it is time to replace it? The P1404 code on this means the egr valve is stuck in the closed position according to my scan tool. Does the drivability symptoms match a stuck closed egr valve?

[GARY C]

Final chapter in this Suburban saga

1999 suburban C2500, stock L31 Vortec 350. Idles “mostly” smooth at idle with just a faint touch of roughness. Runs normal and smooth at medium or heavier throttle, but at very light throttle acceleration or cruise, it bucks, misfires, burbles, etc...and it all clears up as soon as you give it more throttle. I’ve cleaned the EGR valve before...does it sound like it is time to replace it? The P1404 code on this means the egr valve is stuck in the closed position according to my scan tool. Does the drivability symptoms match a stuck closed egr valve?

I had one that would stick and run like crap, I don't know if it was open are closed but you could smack it a cpl times with a hammer and it was good to go for a few months.

[travis]

I’ll have to try that. I really don’t want to spend any more money on this thing.

[CGT]

https://www.napaonline.com/en/p/NDP7002600

Clean it again and put one of tbese on it. Screened gasket....helps to keep it from it getting more crap in it.

[travis]

https://www.napaonline.com/en/p/NDP7002600

Clean it again and put one of tbese on it. Screened gasket....helps to keep it from it getting more crap in it.

Do you live close to there? My parents live just outside of Afton

[pdq67]

Travis,

Did I give you a handful of Chevy lug-bolts the last time you were up here??

If so please send them back to me, I need them to finish my cars suspension is all. All of them...

I will pay you for S&H..

Thanks...

pdq67

[travis]

Travis,

Did I give you a handful of Chevy lug-bolts the last time you were up here??

If so please send them back to me, I need them to finish my cars suspension is all. All of them...

I will pay you for S&H..

Thanks...

pdq67

Not that I remember Paul. I wouldn’t have had any need for them

[CGT]

https://www.napaonline.com/en/p/NDP7002600

Clean it again and put one of tbese on it. Screened gasket....helps to keep it from it getting more crap in it.

Do you live close to there? My parents live just outside of Afton

Didn't realize I gave up my location until I reread my link. I believe Afton is south of STL...I'd be about an hour northish from there.

[travis]

https://www.napaonline.com/en/p/NDP7002600

Clean it again and put one of tbese on it. Screened gasket....helps to keep it from it getting more crap in it.

Do you live close to there? My parents live just outside of Afton

Didn't realize I gave up my location until I reread my link. I believe Afton is south of STL...I'd be about an hour northish from there.

Sorry...it’s a weird character flaw of mine

[1980RS]

Replace the EGR valve. Lot of them have a weak pintle.

[Schurkey]

at very light throttle acceleration or cruise, it bucks, misfires, burbles, etc...and it all clears up as soon as you give it more throttle... ...The P1404 code on this means the egr valve is stuck in the closed position according to my scan tool. Does the drivability symptoms match a stuck closed egr valve?

I don't know why a closed EGR valve would cause those problems.

Stuck OPEN might.

[travis]

Well...that wasn’t it. The old one wasn’t stuck, and the good used one I just replaced it with made no difference at all.

This thing is acting just like it did when the TPS went bad. The TPS was replaced maybe a year ago. I have rechecked it and see 0.65v at idle, 4.69v at WOT, and a smooth linear voltage increase from idle on up.

This engine is tired, which isn’t helping the troubleshooting at all.

[dannobee]

Are you sure that the passages in the intake manifold aren't plugged up?

[travis]

Are you sure that the passages in the intake manifold aren't plugged up?

I cleaned everything out when I replaced the intake gaskets and spider injector assembly last year. It “shouldn’t” be clogged.

[dannobee]

Do you have access to a full feature scan tool? If so, command the egr valve to 100% and see if it dies. If it doesn't, the passage is plugged somewhere.