infamous p0300 with others [Archive] - GrandAmGT.com Forum

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imtfox
09-18-2006, 09:03 PM
My sisters Grand Am is running very poorly. I pulled the codes today and I got a P0108, a P0105?, and the famous P0300. As far as I can tell, the misfire 300 code is probably the real symptom and the other MAP sensor fault and MAP sensor too high codes are a result of the misfires. My first inclination is to do the plug wires because I don't think it's a MAP sensor failure (and the MAP sensor is $65 and non-returnable). Any other places I should look?

jackal2000
09-18-2006, 09:28 PM
PO300 usually means one of the following

* Faulty spark plugs or wires
* Faulty coil (pack)
* Faulty oxygen sensor(s)
* Faulty fuel injector(s)
* Burned exhaust valve
* Faulty catalytic converter(s)
* Stuck/blocked EGR valve / passages
* Faulty camshaft position sensor
* Defective computer


i highly doubt that the misfires are cause for MAP codes. i think you have 2 separate problems.

imtfox
09-18-2006, 09:47 PM
What type of problem would normally cause a MAP too high then?

jackal2000
09-18-2006, 09:59 PM
ummm a bad MAP sensor or wire?? lol whats happening is your sensor is getting too much voltage causing it to malfunction.

imtfox
09-18-2006, 10:23 PM
I thought the MAP too high was saying the pressure in the manifold was too high... ie the vaccuum line part had too much. If it's strictly voltage, then I should just go ahead and spring for the MAP sensor?

Can it go the other way where a bad MAP sensor can cause the car to run like poop? (throwing the P0300)

jackal2000
09-18-2006, 10:25 PM
i really am not sure if the two are related.

check this
http://v8sho.com/SHO/Update8.gif

imtfox
09-18-2006, 10:33 PM
*Right click* *print*

Sweet!! I think I'll swap the plug wires first to see if that clears the misfire problem. Then if it's still setting codes for the MAP sensor, then I'll look at swapping that out too.

Thanks for your help. Anyone else still feel free to chime in with any tips!

GA SE/T
09-19-2006, 01:26 AM
Thanks for your help. Anyone else still feel free to chime in with any tips!

I'm in the same boat as you. Car is showing same code (P0300) except I have a 2.4 and no MAF sensor. *sigh* ;crap

imtfox
09-19-2006, 10:52 AM
I'm in the same boat as you. Car is showing same code (P0300) except I have a 2.4 and no MAF sensor. *sigh* ;crap

Well I got the car today and found out it was the 2.4L... so I had to go back to the parts store and get the direct ignition connectors. It solved the problem. She also has two leaky valve cover gaskets which I think was contributing to the problem because there was some oil in the plug wells. I'll have to fix that next. No MAP sensor codes anymore so I'll keep my fingers crossed.

imtfox
09-19-2006, 07:38 PM
Well crossing the fingers didn't help. She said the light came on after the car warmed up and it shifted into a higher gear. It sounds fine at low (>1500 RPMs) but once it gets up higher (<2000Rpms) it gets rough throws the P0108 code and shifts rough. Any ideas on this one???

jackal2000
09-19-2006, 07:56 PM
MAF sensor is not the same as MAP sensor

MAF = Mass Air Flow

MAP = Manifold Absolute Pressure

check the MAP sensor, dont ask me where it is cause i dont know, i have a 3400.

imtfox
09-20-2006, 07:31 AM
I found the MAP sensor... it's on the front side of the air intake. On a hunch I did a "tug test" of the vaccuum hose and sure enough the dang thing disintegrated at both connection points. It looks like it had been worn through at the MAP side for a while so I hope that is what was making it throw the code. I'll get more hose today and see if that fixes it.

imtfox
09-22-2006, 02:05 PM
well with the new hose, the car ran better for a couple of days. Now it makes this horrible rattling sound and dies quite often. I need to go get the scanner again and see if there are any new codes but it almost sounds like the valves toward the rear of the motor are clanging...

jackal2000
09-22-2006, 03:00 PM
have you looked at the spark plugs yet?

imtfox
09-22-2006, 03:26 PM
I haven't pulled them yet. The new boots seemed to fix the p0300 code so I didn't bother pulling them. Am I looking for gap, fouling, icky stuff?

I did notice the valve covers were leaking some oil but it wasn't terrible.

jackal2000
09-22-2006, 04:46 PM
Am I looking for gap, fouling, icky stuff?
yes

imtfox
09-23-2006, 01:47 PM
Well I found out what the knocking was this morning as I went to start it up and one of the pistons exited the block... So it looks like it's time for a new motor. I'll probably spend Monday on the phone and the next month doing the swap... :rolleyes:

jackal2000
09-23-2006, 02:22 PM
damn good luck with that

swap in an ecotec

imtfox
09-25-2006, 09:10 AM
What's the difference?

jackal2000
09-25-2006, 12:00 PM
What's the difference?
i think GM beefed one up to 1,000hp, good luck getting that out of LD9

imtfox
09-25-2006, 03:12 PM
i think GM beefed one up to 1,000hp, good luck getting that out of LD9
LOL... I'd settle for one that doesn't self detonate. :D :D