Hey guys, I used to post here quite often but I've been so busy for about the past year and my car had been running so well and I just re-registered because I forgot my password. Just letting everyone know that I'm not new here (I've already searched for the answer to my question and all). But now I have a major problem and came to the #1 source of good advice. Well it started about 2 weeks ago, every now and then I noticed my idle would be a little rough (slight miss), but it went away for about a week and a half until a couple of days ago my car just starts missing horribly throughout the entire RPM range, and it will not throw a SES light right away but after about 5 minutes of driving with the miss, the light will come on and the miss immediately goes away. It seems like the computer is tricking itself though, because after about 5 more minutes of running decent while the SES light is on, it will go off and the miss comes right back and it just repeats this cycle. What systems are disabled when the SES light comes on? I know the MAF, but I already tried unplugging that and the miss was still there. I really do not want (nor can afford) to pay a shop 60 bucks to pull the code, tried Auto Zone but all they had was the cheap GM code scanner that does not work with these cars. I am also certain its not plugs and wires since I kow that is a popular response to misfire questions. Thanks for your help guys,

Derek

 

Well Derek, you have a choice here. This could be one of the following solutions, or a combo, or even all of them!

Here goes, from the cheapest to the mostest...At least I think this is the order:

Fuel filter.
EGR valve. Clean it, see what happens, or buy a new one.
Spark plugs &/or wires.
Fuel pump.
cracked vacuum hose/hoses. You'll will have to spend some time to figure out which one it is, or replace them all.
Smog pump.
OptiSpark.

Or any combination of those.

I think that's about it...Yeah right! If you can't afford 60 bucks, then you may have a problem for a while there.

Chances are, it's the Opti.

 

I'm sure its not the Opti also, just replaced it in January.....my experience with an Opti failure is that it gives you about 15 minutes of warning before it goes. I was just checking some things out a few minutes ago, and I might have found my problem. I discovered that my right side O2 sensor wire is touching a primary and it has burnt through the heat shrink wrap and the wire insulation.....when you get a SES light does the PCM go back into open loop? Will a malfuctioning O2 sensor cause a miss when in closed loop? Thanks again,

Derek

 

Dangit, I forgot the O2 sensor thang!

My bad!

And good for you finding the O2.

RE: PCM, I have no knowledge.

BTW, did you buy that Opti NEW, or refurbished??? Cuz I have learned through quite a few camaro websites, and MY OWN CAR that our beloved LT1's do NOT like refurbished Opti's...

Future food for thought.

 

Carlos,

Definitely bought a new Opti from dealership, I've heard way too many bad things also about Adavance Auto/Auto Zone crappy opti's,

Derek

 

Here is an update, I fixed my O2 sensor wire and that did not help things at all. I found a place to scan it for 25 bucks so I went and did that and I'm just as confused as before, here is what they found:

Code 48: MAF failure - this can be explained by the day I unhooked the MAF to see if that was the problem (see first post)

Code 64: Right Bank O2 sensor reading too lean - I would think this would be explained by the burnt right side O2 wire

Code 32: EGR - this code pops up every now and then because I blocked off EGR a couple years ago

There was also a cooling fan code, probably set by my manual fan switch.

So I am basically at square one again, my thought now is that since the O2 was reading lean it was dumping extra fuel into the engine to compensate and possibly fouled up a plug or two? Any suggestions would be greatly appreciated! Thanks,

Derek

 

One more thing, if it was a plug, that would not explain why the problem goes away when my SES light comes on.

 

After a couple days of work that included inspecting all underhood wiring, taking my plugs out and wires off, replacing my right side plugs because they were all black with carbon and replacing my right side o2 sensor (the slits that let the exhaust gas into it were gunked up with carbon) all seems to be well again with the Z. Turned out to be a simpler solution that I thought.

Derek

 

My car was maybe is havent tried it yet i changed 1 wire and started pushing on all the wires thats pluged into the opti well 2 clicked when i pushed on them so maybe at idle they were touching but during acceleration they were vibrating so much they couldnt touch enough to ignite the fuel? Ill drive it in about 20 minets but that was odd i thought that they clicked like they werent pushed on all the way, just a though for you all!