DeeKay

will you make a sound clip reving from idle to about 4k on and off, soft and medium throttle? curious as to if the sound matches revs.

a damaged catalytic converter can be problematic causing misfires and drive-ability issues and generally overlooked. May or may not be your issue, just add it to the list of things to inspect. You can remove the o2 sensor and plug in a backpressure gauge and if the cat is clogged the needle will basically peg out (6-8psi) however anything over normally 1psi is bad.

I'd also advise to install new oem plugs.

A backfire is either caused by a lean condition, misfire, which allows unburnt fuel in the exhaust system or a rich condition which also can enter the exhaust system, backfiring. Other things to take a peak at, pcm, software (flash), map, wiring, injectors.

TixonPB

I'll work on making another video with revving, but the sound does go with it. It gets faster with the revs and it's present at all times. When I pulled the old plugs there wasn't the usual black sootiness or wetness that I would think indicates the car running rich. When my OBDII-to-usb gets here i'll be able to watch what the computer is doing from live feed. How will the fuel trim # follow a rich or lean condition? I'm hoping to find someone to swap coilpacks with in my area to see if that solves it as well.
I haven't thought to check the cat yet. What kind of backpressure gauge would I use to inspect the catalytic converter?

TixonPB

I noticed something on my drive home tonight. Even after warm, if I tried WOT under 3500-4000 rpm, it would backfire and bog terribly but no misfire code still. It didn't matter what gear. Under 3500 WOT would bog. Over that, she runs like a champ thru to 9k. I'm scratching my head at what could cause her to bog at low RPM like that but not affect the rest of the power curve, like it literally overpowering what is causing the problem in low RPM. Any ideas anyone?

S2Krazy89

Do you have an OBDII scanner? scan it check which cylinder is misfiring, then clear it. Swap the bad cylinder coilpack with a working one. Then if it throws a CEL, check if it's the same cylinder as before. Then you'll know its a coilpack or not. Mine just went out today too. Your local auto part store doesn't lend out OBDII scanners?

S2Krazy89

Map sensor would be my guess for that, if it revs freely at high rpm.

TixonPB

I have a diagnostics software on my computer to run with the car when my plug gets here tomorrow, because I lost my old OBDII plug. last I checked I had no codes with misfire though. That's what seemed odd. Is there a way to test to see if the map is bad before buying another? I did the map whack and ziptied it, but you think it could still be bad?

DeeKay

I'm not sure on the specifications yet possibly you could read the voltage range with a volt meter, however I'd suspect a code if that were the case (bad sensor).

Based on the description of the noise, my suggestion would be to start with the valvetrain. You are describing a camshaft noise.
http://www.tooltopia.com/tool-aid-33600.aspx

TixonPB

I'll know for sure about the code tomorrow when my cable comes in.

S2Krazy89

It may not be sensing enough air at lower rpm. They don't last forever, especially if you're using an aftermarket filter. MAP whack is just a band-aid if you ask me.

I would try to eliminate that it's not the coilpack first but based on you you describe how it revs freely at high rpm, i'd look at the MAP. Eliminate the things that don't cost money first.

Also, I think DeeKay is suggesting you get a compression test. It'll tell you a lot.

TixonPB

I did a compression earlier today, as I posted earlier. I got readings of 230-225-227-231. I have a K&N Intake with Filter. Is there a way to eliminate the MAP without buying a new one? Tried the MAP whack again but it didn't change anything.