[AC_Photo]

Hi I have been reading the forum trying to figure the surging problem out on my daughter's 2000 Malibu. It cruise's fine, but when setting and idle it runs rough then worsening when idle in gear. Though takes off and cruise's fine. I have ran my scanner and replaced the following laundry list.
EGR valve (though new code for EGR came back)
IAC
TPS
Upper and lower intake manifold gaskets
Injector orings
Plugs
Wires
Coil packs
O2 sensor
PCV
PCV tubing
Fuel pump
Probably forgetting others
Ran smoke to try and find a vacuum leak the only thing was the tube to the valve cover under the coil packs. Before I buy another EGR I figure I would ask. It's throwing codes for p0300 misfire
P1404, p0404, and p0131
I'm stumped
Thank u in advance
Adam

 

[DrivenDaily]

Maybe you can share what engine it has and how many miles?

 

[AC_Photo]

My apologies yes it has a lot at 208k and it has 3.1l
I was reading somewhere to check the ignition module.
Thank you

 

[Drunken Elvis]

There was a member here a few years ago by the name of RalphP He did a lot of work on the car/engine you have and was a good source of info. Try using the search feature of this forum and specifically posts by RalphP, you may find the answer to your problem.
One such search yields the following thread... surging

 

[AC_Photo]

Thanks

 

[Darthz]

I saw you replaced injector o rings.... there is a chance you have leaky injectors. .. sometimes dirt interferes with the pintal closeing all the way..... Sometimesthis can be checked by seeing how much preasure drops in tue fuel system after priming

 

[AC_Photo]

 

[AC_Photo]

Some pics of the codes it's throwing.
Thanks again

 

[Darthz]

Is all them pics....when it's idling? Tps say 14%....is that at zero throttle? I had to calibrate mine on my IROC before

 

[AC_Photo]

Car was just in the on position. Got it figured out. The EGR valve I installed failed. Took back new one installed and no more rough idle or surging.
Thanks a bunch