nathan96

I am having a hard time trying to figure out whether this code is being caused by the optispark or the O2 sensors. I ordered some new sensors since they might have been fouled by the Longtubes, but if they are messed up, wouldn't they set off a code too? I have tried plugs and wires and made sure the routing was good on them, but the car is running very rich, soot on the back of the garage door, rich. I guess until I install the O2 sensors I will not know for sure, but what are some opinions here? Oh, and what are the details about the air reference for the O2 sensors that I saw a while ago when searching this since I extended mine?

Injuneer

P0300 indicates "random misfires". Could be from virtually any cause, including ignition problems, injector problems, valve train problems, etc. Can even be set by excessively rough roads, and a more agressive camshaft. I wouldn't jump to the conclusion that it has to be the O2 sensors or the Opti.

Running "rich" is often the result of exhaust leaks before the O2 sensors, misfires or faulty O2 sensors and/or extensions.

You need to systematically eliminate all the possible causes. A good data log, from a system like AutoTap might provide some guidance as to the real problem.

nathan96

I agree that I need to eliminate possible causes, I am going to try and log all of the readings that I can with my HPP3 powerscan unit tonight and see what it says. I may check around locally to see who has an autotap too, or maybe datamaster. I have not changed the O2 sensors since I bought the car, and suspect my skill on extending the wiring to the long tubes. The car has over 75k on it too, so it cannot hurt, at least it rules one more thing out that probably could stand to be replaced anyway

rocmemphis

9 times out of 10 a P0300 is from bad spark plugs or wires.

With headers I would bet you have a burnt wire and sometimes it can be really difficult to spot. The only sure way is to pull them out and check.

nathan96

I agree, that is why I replaced the plugs and wires first to determine if that was the cause. I thought that it had to be since one of the wires had a burnt mark on it, but it has gotten worse since.

nathan96

Found a guy who has Autotap, what settings should we try and make sure that we record to try and solve this problem?

Walkovaya

i had a bad upstream o2 that caused the above code on my 96 ta ...got new o2s and had no more problems...so my response is yes bad o2s can be the caused...but there are a bunch of other potential and more probable causes.


good luck figuring it out.

nathan96

Well, I used the powerscan module tonight and believe I may have figured out the problem, or at least most of it. The alternator seems to only be working about half the time, because it would let the battery drift down to about 10.8volts then try and charge it back up some, then back down. I pulled it out and the brushes are about gone and the holder was broken in a couple of places.

texas_z28_guy30

i think i read somewhere that a blinking SES light indicates continuing misfires. Is that true? (Sorry i didn't mean to take away from your problem)

nathan96

Yep, that is a random misfire code on all cylinders. It is not the best of codes, but it is the only one I am getting, and the alternator seems to be guilty right now.