Still reading P0300 code. HELP!! 2002 GA 3.4 Liter [Archive] - GrandAmGT.com Forum

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Robc
11-08-2011, 07:48 AM
I'm stumped on this one!
I have a 2002 Grand Am GT with 3.4 liter 115,00 miles.

Heres what happens... It starts and runs great while driving for 2-3 minutes then it has a constant hesitation with no power once it is warm and is eating gas like a hog.

First reading of codes was a P0300 scan code with multiple misfires and a Cat code that I cant recall.

Heres what I have done in order so far.
1- Replaced plugs and wires... didnt fix it. Now reading P0300 only.
2- Seafoamed as suggested by Advanced Auto when I had the code reread... didnt fix it.
3- Replaced ignition module and all 3 coil packs... didnt fix it.
4- SES light went off but still the same symptoms that occured with light on as said above. Reading no codes.
5- Now, 1.5 days after light went off the SES light is back on.
6- Immediately went back to Advanced to have the code read again... Reading P0300 again.


Any suggestions.... maybe one of the cat converter sensors?

YEP!!...Still Stumped!

Pauljp
11-08-2011, 09:51 AM
Sounds like the symptoms of a clogged catalytic converter.
Try disconnecting it and see if the symptoms are still present.
It will be loud of course, but only for a short time.

Robc
11-08-2011, 09:54 AM
Sounds like the symptoms of a clogged catalytic converter.
Try disconnecting it and see if the symptoms are still present.
It will be loud of course, but only for a short time.

Whats the process to hollow it out?

03Sleepr
11-08-2011, 11:57 AM
Whats the process to hollow it out?

if its clogged then you will have to get a new one.

to find out if the cat is your problem just remove it and see if the code goes away

Robc
11-08-2011, 01:06 PM
I read somewhere on this forum you can hollow it out when I was exploring the problem I have.

Pauljp
11-08-2011, 03:25 PM
Hollowing it out will just give you another problem, your second O2 sensor will give the same reading as the first O2 sensor, thus tripping the MIL, unless you install an anti-foul plug on your #2 O2 sensor to take it out of the stream. Still, easily done if you want to go that way.
First you just want to see if the cat is the problem. Just unbolt it and separate the pipes before the cat, so you have unobstructed exhaust. Start the car (it will be loud) and let it run for a few minutes like you did before and see if the symptoms are the same. If your car runs great, then it is most likely the cat (or some other blockage down the line. If you still get the same symptoms as before, then it is something else and your cat is probably fine.
Either way, it's a simple test that doesn't cost anything.

traysvega
11-08-2011, 03:57 PM
You could also pull the o2 sensor out of the rear manifold and drive it to see if the power returns rather than removing the cat first(just dont drive it very far like that).Also with clogged convertors alot of times the back pressure will also set egr codes.As stated hollowing the cat out will only result in setting a p0420 cat efficiency code.SES light will be on.

Robc
11-09-2011, 03:46 AM
If I do hollow it out, what is the easiest way to do it?
As far as the anti-fouler for the o2 sensor... will I need to drill it out or just install as is when purchased.