P0300 Problem??
Thread Starter
Intermediate
Joined: Apr 2007
Posts: 28
Likes: 0
From: Red Deer Alberta
P0300 Problem??
I have a 02 Z06 and I just installed headers, high flow cats, X pipe, B&B bullets, and Cold air......... Now my car back fires only at low RPM and idle every now and then and pulling a P0300 code. I put new plug and wires still same problem?? Can any one help!!! Thanks
Melting Slicks
Joined: Oct 2005
Posts: 2,877
Likes: 9
From: Ottawa Ontario
I have the same issue....I cannot figure mine out as well. I have changed all my plugs, wires, etc....Don't see any chaffing on wiring harness either. Mine seems to be at low rpm/Idle as well. i have my cam values raised for misfire right now as well. So this has been bugging me for a while now 
Last edited by MotleyDrew; Apr 14, 2008 at 08:18 AM.
Thread Starter
Intermediate
Joined: Apr 2007
Posts: 28
Likes: 0
From: Red Deer Alberta
Don't know. I found a tread on P0300 but ended up being wiring on coil#7 but I'm sure thats not the problem in our case..... I checked and double checked all wiring, plugs and had my cars computer reprogramed with LS 1 edit. My coil packs should be good b/c it was running good before the mods, but cant rule it out for sure. I would like to test the coils before starting to spend unnessary money on new ones. I am thinking oxygen sensors????? Could that throw a P0300 code? What about O2 simulators... What are they and what do they do?
Last edited by CanadianZ06; Apr 14, 2008 at 09:25 PM.
Le Mans Master
Joined: Aug 2005
Posts: 5,375
Likes: 328
From: CA.
St. Jude Donor '13-'14-'15
You didn't say what you did with your AIR tubes--did you block them off ? Also did you install 02 simms in the rear 02's or have them programmed out ?? As mentioned you can set the misfire tables to the MAX values--But i that normally is for false misfires--If you are getting a backfire--that usually points to a real misfire--
I would check the fuel trims to see if it could be a fueling problem --vacuum leak--Did you plug off the AIR pump inlet hose ? A lean condition could cause a misfire--but only if your computer isn't correcting the 14.68 closed loop fueling fast enough--What about the MAF screen ?? did you take it out ?? Check for exhaust leaks !!
If not a fueling issue--then that leaves ignition--maybe the same plug keeps closing the gap when you install it--bad coil--missing grounds--
Good luck---
I would check the fuel trims to see if it could be a fueling problem --vacuum leak--Did you plug off the AIR pump inlet hose ? A lean condition could cause a misfire--but only if your computer isn't correcting the 14.68 closed loop fueling fast enough--What about the MAF screen ?? did you take it out ?? Check for exhaust leaks !!
If not a fueling issue--then that leaves ignition--maybe the same plug keeps closing the gap when you install it--bad coil--missing grounds--
Good luck---
Melting Slicks
Joined: Oct 2005
Posts: 2,877
Likes: 9
From: Ottawa Ontario
You didn't say what you did with your AIR tubes--did you block them off ? Also did you install 02 simms in the rear 02's or have them programmed out ?? As mentioned you can set the misfire tables to the MAX values--But i that normally is for false misfires--If you are getting a backfire--that usually points to a real misfire--
I would check the fuel trims to see if it could be a fueling problem --vacuum leak--Did you plug off the AIR pump inlet hose ? A lean condition could cause a misfire--but only if your computer isn't correcting the 14.68 closed loop fueling fast enough--What about the MAF screen ?? did you take it out ?? Check for exhaust leaks !!
If not a fueling issue--then that leaves ignition--maybe the same plug keeps closing the gap when you install it--bad coil--missing grounds--
Good luck---
I would check the fuel trims to see if it could be a fueling problem --vacuum leak--Did you plug off the AIR pump inlet hose ? A lean condition could cause a misfire--but only if your computer isn't correcting the 14.68 closed loop fueling fast enough--What about the MAF screen ?? did you take it out ?? Check for exhaust leaks !!
If not a fueling issue--then that leaves ignition--maybe the same plug keeps closing the gap when you install it--bad coil--missing grounds--
Good luck---
Thanks bud ! My car doesn't seem to back fire except when getting off the throttle and its more of a little popping than anything. I have removed the Air Pump system from my car. I don't belive I have any vacuum leak as when I data log it my vacuum holds steady. My MAF screen has been removed ! Don't think I have an exhaust leak and my rear 02's have been tuned out as I don't even have anything plugged into them.
Thanks for the help!
Thread Starter
Intermediate
Joined: Apr 2007
Posts: 28
Likes: 0
From: Red Deer Alberta
Thanks! I checked for Vauum leaks, exhaust leaks, and have my rear O2 sensors dissabled. I checked plug and wires last night then took out my car for cruse and it got worse....So i think it has to do something with spark, Maybe bad coil. Can you disconnect the air tube from header to header??? I have my hooked up still......Would it help? I been reading on the forum and be seeing spark plug gap at .040 I have my at .045 thats GM recommemded gap could that make a difference? Could just be anouther bad set of plugs and wires again!! Thanks !!
Melting Slicks
Joined: Oct 2005
Posts: 2,877
Likes: 9
From: Ottawa Ontario
Thanks! I checked for Vauum leaks, exhaust leaks, and have my rear O2 sensors dissabled. I checked plug and wires last night then took out my car for cruse and it got worse....So i think it has to do something with spark, Maybe bad coil. Can you disconnect the air tube from header to header??? I have my hooked up still......Would it help? I been reading on the forum and be seeing spark plug gap at .040 I have my at .045 thats GM recommemded gap could that make a difference? Could just be anouther bad set of plugs and wires again!! Thanks !!
