Thread: Car throwing CEL

Originally Posted by dmack976

I have a 2001 GTP that is acting funny. The car was running fine this morning. My wife goes to drive the car home and the CEL came on. She said the car was sputtering also the check engine liht flashes after you go over 35 . Took the car for a ride around the block to PEP Boy and had the codes ran.. I got P0306, P0137t ,P1133. My brother seems to think it is the O2 sensors. I got both 02 sensors. Has anyone else had theses issues?

A quick google search says p0306 is cylinder 6 missfire. I have also found that in some people's cases (google) a missfire triggered p0137. I'd fix the missfire first and clear the codes to see if the other ones come back. If they do I would test your o2 sensors before just replacing them (or it) because it seems that doesn't always fix the issue.


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Originally Posted by Explicit_Spade

Bank 1 is the o2 sensor upstream of the Cat. Since you aren't throwing any bank 2 codes, I wouldn't bother replacing the downstream o2.
Make sure you don't get a splice in style 02 sensor.

This still doesn't explain the miss on cyl 6. You may want to take a look at the plug, wire, coil pack and injector for that cylinder.

^ agreed. You could try swapping the #6 plug wire with a different Cyl and see if the missfire changes cylinders. You can also start the car at night and spray the spark plug wires and coils with water. (A fine mist from a spray bottle will do) then look for the wires/coils to ark.


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well according to AutoZone P0306 The power train control module monitors the crankshaft speed and has detected a misfire condition.

Probable cause:
Ignition system fault-spark plug(s), ignition wires, coils
Vacuum leak
injector fault
high or low fuel pressure

It seems like both bank are throwing a code for 02 sensor. I guess my question would be does it makes sense that if both 02 sensor go out it would send a P0306?

I am new to the 3800 scene but I wouldn't think bad o2 sensors would cause a missfire. Come to think of it, I just started my car the other day open headers with no o2 sensors and didn't get any misfires. Prolly just a leak in the ignition system somewhere.


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Quick update... found the #6 wire was burned in two spots. Plus my 02 sensor was very loose. The car has stop stuttering. I got a new spark plug wire. I do not think the 02 sensor are bad. So I more then likely return those sensor and get my 116 bucks back. Once my car cools down I will change everything and update you all. Just happy it is not looking like I need a ICM or a new coil.

Heck, I'd rather change the ICM or a coil before having to screw w/ #6 cylinder and the O2 back there, lol... Used ICM and coil from a JY is cheap(er). Good that you got it figured out.

well we hope this is what fixes it...... Just by looking at it a wire that is burned and a loose 02 sensor would explain the issue. Once my car gets cool enough I will change them and see if that fixes it.. But thanks everyone for you input.

I had to get my kids from school too. So

Hell yea my motor bay gets hot as hell.I have already been burned once before!!!The cable auto zone gave me was to big... They gave me 8mm instead of a 7mm. so I have to take another trip to the auto part store

Originally Posted by BillBoost37

Another happy customer!

Fordy.. c'mon.. #6 is cake and the O2 doesn't have to fight. (I really miss that Bonne exhaust manifold when working on a GP though)

At least nobody mentioned unhooking the front mounts and rocking the engine forward for more space back there. I agree on the Bonne. My 95 is easier than my 00 GP for sure.

dmack- Pop the hood and drink a beer, then change the wires and O2. 12oz. is usually enough cooling time to get started. Then start car and drink another beer while you listen to it purr