1999 3.1L bad hessitation/bogging on accel

[CountryV8]

Hi y'all! New to the forum, hoping to get help.

Got this 1999 Buick Century 3.1L with 156k km (98k miles) and has such a bad case of hessitation on acceleration from any speed, but more from a dead stop.

From a dead stop, you step on the gas in a casual way, will feel normal, then as soon as you get moving, it wants to die, bogs, won't go, floor it, nothing, keeps bogging. Onces up to ~40MPH, drops a gear and takes off like a rocket! Acts like it's taking off in 2nd gear sometimes.....

But also from a dead stop, when it bogs, if you let off the gas then press it again, it's fine most of the time.

Disconnecting the EGR helped, but still does it, not as offten though. But always has a small affect.

Also many random times, crusing down the highway, even on the cruise control it starts acting weird, bucking, running like crap, but keeps it's speed. All it takes is to either apply a tiny bit of pressure on the gas pedal and it cures it, or letting off the throttle also cures it?

I have cleaned the MAF sensor. No change.


The ress i'm posting just in case it's related to the buckin. __________________________________________________ __________

Electrical problem:

Service Engine soon light is on

Service vehicle soon light is on
and ABS light is on along with Trac Off.

Heres the funny part. The one that stays on most of the time is the Engine light.

Sometimes you start the car, nothing in the dash is on.

Just driving down the road, they all come on, or just 1 of them.

Other times (most common) start the car, Service Engine is on. Back up or drive forward about 20 feet and ABS and others come on.

Rare times but has happen quiet a few times, all the lights go off driving down the road!



Can someone please help me???? I'm good working on old cars, but not newer ones. Especially not electronics!

Also have 5 codes:

PO404
PO405
P1404
P1610
P1626

I have checked them all, but don't have time or enough skills to start screwing around with all the stuff that can cause all of this.

Please help!

[maxwedge]

Welcome to AF, no quick answer here, the first 3 codes are egr related, it is either stuck part open or fails to respond to pcm commands. The last 2 a manufacturers specific codes. The abs must be scanned with a specuial scanner to track codes and look at speed sensor inputs.