Ok - kinda confused here and need any ideas:

Please bear with me - I know its long but I tried to include anything that might be useful.

On Sunday, on the way to a buddies house (to install Hooker headers/y-pipe on my car), my SES light flashes then goes to steady (no longer flashing). I pull over for gas - turn car back on - light is gone and stays off for the remainder of the trip.

Get to buddies house, ATAP the car - it shows a misfire on #5. Car is not acting differently at all - pull plug and see nothing strange at all. Start car back up - still no light. Figure it was just a "freak" incident and dismiss it.

Header/Y-pipe install goes smoothly. No complications. Car fire's right up and sounds great. No SES light - nothing. Drive it back home that night uncapped - loud as hell.

Following morning (monday) I take it out - cap it up (still sounds good) and drive it around for an hour cause of the nice day. No SES light or anything - car was running good.

Same thing Tuesday - drove it about 20 miles to meet some friends (still capped) - no SES light.

Last night something weird happend. I stopped to get gas. When I turned the car back on after filling up - the Change Oil light came on (not just the startup/check light). Didnt make much sense - oil was changed at just over 12,000 miles and it now only has 14,400. Seems a little quick to me - maybe nothing at all but it has me worried cause of what happend next.

I meet up with some friends a local car gathering frequented by a lot of import cars (teenagers driving Honda's w/ fart pipes basically). So to make our pressence a little more known, we all decided to roll through uncapped (I am the closest to stock out of the bunch - a couple are heads/cam cars). So I uncap, stroll through the lot and park. Still no SES.

After sitting for about 2 hours, I decide I need to head home. Fire up the car (change oil light on again) and notice the SES light is flashing. WTF? I immediately start freaking out thinking my engine is gonna go cause my headers are screwed up - LOL. I shut the car down and my buddies and I give it the once over checking oil levels, looking for vibrations, any signs of misfiring - nothing seems out of the ordinary. So I fire the car back up and the "change oil" light comes back on and so does the SES light but this time it doesnt flash, just stays solid. Car sounds fine - idles smoothly, etc. It remains on the whole ride home (about 10 miles). I drive very easily to be on the safe side. Did goose it a little right outside my house to see if performance was being impaired but again nothing - car felt really strong. Things werent making sense - still dont.

Several causes pop into my head but with each, there seems to be a reason why that wouldnt make complete sense.

1) a misfire? car drives perfectly fine - no vibration at all - performance is strong

2) bad O2 sim? maybe one of the sims got too close to the exhaust pipes and melted thus throwing the emissions code. Would make sense why the code was there but no other function of the car was impaired. But we were VERY careful to mount them out of the way of the heat source. Have not checked yet though.

3) opening the cutout? code was not being thrown when capped. didnt pop up until 1 engine cycle after uncapping. maybe the adjustment made in the exhaust flow triggered the code.

4) EGR? the Hookers i ordered had an opening for EGR. My car being an '01 doesnt have the EGR. However, no block off was sent with the headers. We fabricated a peice of aluminum to cover the opening. It was grinded to shape, installed a gasket and bolted it down. While I dont see a leak, if there was a small one present, could this throw a code like this?

5) untightend gas cap? Since I just got gas. Would throw a steady SES light - but not a flashing one.

6) Why would the SES light flash one time, then the next stay on solid?

ANY ideas or possible causes would be greatly appreciated. First track outing with this new setup is supposed to be on Saturday but I dont want to drive it if there is ANY chance I could do ANY damage.

Thanks guys.

Will

 

Will, let's take it a step at a time. The misfire you logged with atap and noted cyl #5, was that the case on the second time as well? If so, rule out everything you were suspecting in your list and focus on that particular cyl. First off, I would make sure all plug wires on drivers side are securely connected. Then I would inspect that plug and #3 & #7 as well (sometimes adjacent cyls will actually misfire and ECM will flag the wrong cyl). If plugs look ok, I would then start swapping things. Plugs, wires, coil packs one at a time with other locations and watch for the misfire to move accordingly. It appears it's only happening for a very short time and then stopping which is why you see it flash and then go steady (the steady SES is just latching the misfire code which it was previously monitoring).
Of course, I'm assuming that you are only getting the misfire on #5 and no other cyl. If it's random, let me know.

 

Not sure yet - only time it was ATAP'd was Sunday for the orginal SES light (and it was a steady then - i think i said flashing) - ATAP showed a code for a misfire in #5. Everything looked fine upon inspection - never saw anything after that.

Havent ATAP'd the car since last night when I got the flashing SES light. Heading over Haole_boySS tonight to run it (might stop by Advanced to get it checked also). I will have a code then if its still on.

 

Even if the SES goes off, you'll still be able to pull the code from history. If you're gonna be down this way any time soon, I also have a few different scanners available. I'm also free this weekend if you want to try and hunt this thing down. There's a few different things we can try and look for on the scanner.

 

Good deal - how far are you from me? I actually live in Bryantown (about 10 miles south of Waldorf down Rt 5 towards you)?

I am supposed to be heading over Andy's house tonight - he has my car logged in on his ATAP so we should be able to pull the codes.

Hopefully it is nothing, I am trying to test the new setup out on Saturday but not if I cant figure it out.

From what I am telling you - you think I could be doing any harm driving the car - he does live 20 miles from me.