misfire under boost?

[kannon]

After having a great run of luck with things, I guess now I'm due.

Here is the short version. 99 Si, JRSC w/stepper, hondata, 440cc, J&S classic, bosch pump.

When I go WOT after about 2-4 seconds i hear what sounds like a machine gun from my exhaust. now, keep in mind I have a 3" thermal, so ALL i hear is exhaust. When I hear the sound, I also feel the car lose power. It almost feels similar to when the J&S pulls timing... but the J&S indicates NO activity. Fuel pressure seems just right. My cheesy autometer Air/Fuel still indicates rich. Oh yea, NO CODES. maybe it isnt a misfire?

I havent gone through the full gamit of research cause its been cold and rainy, so I thought id get people thinking before I start pulling things apart.

What I was going to check:
Plugs.. maybe its detonation
ignition connections
run hondalogger and watch the o2 values

Any other ideas?

<font color="#a62a2a" size="1">[ October 15, 2002 08:24 PM: Message edited by: kannon ]</font>

[i2un]

Once, when I had a misfiring problem it would always happen at higher RPM's (like +6000). It was like the car hitting a wall of severe detonation at 6k. I ended up just doing a much needed tune-up...plugs, wires, cap and rotor and it cured my problem.

<font color="#a62a2a" size="1">[ October 15, 2002 11:25 PM: Message edited by: i2un ]</font>

[kannon]

<BLOCKQUOTE><font size=2 face="Verdana, Helvetica, sans-serif">quote:</font><table border="0" width="90%" bgcolor="#333333" cellspacing="1" cellpadding="0"><tr><td width="100%"><table border="0" width="100%" cellspacing="0" cellpadding="2" bgcolor="#FF9900"><tr><td width="100%" bgcolor=""><font size=2 face="Verdana, Helvetica, sans-serif">Originally posted by i2un:
Once, when I had a misfiring problem it would always happen at higher RPM's (like +6000). It was like the car hitting a wall of severe detonation at 6k. I ended up just doing a much needed tune-up...plugs, wires, cap and rotor and it cured my problem.

<font color="#a62a2a" size="1">[ October 15, 2002 11:25 PM: Message edited by: i2un ]</font></font></td></tr></table></td></tr></table></BLOCKQUOTE>

Good suggestion. Unfortunately, all my ignition equipment is new within 10k miles. Rotor, Cap, Wires, Coil. Im leaning toward detonation, I just wonder why the J&S isnt picking it up. It is still reacting when I expect it to though, so i think its still working.

[waveoff]

Whenever it's wet outside and my TPS wiring is about to come undone my car behaves the exact same way. Machine gun exhaust, a/f gauge shows rich even though a bunch of led's are lit up, only happens under boost. It takes a few minutes of this behavior before I throw a random misfire code and/or low/high TPS voltage code. I used to get the same behavior before the TPS hack due to a leaky distributor cap. The hole I had drilled in the cap for my MSD wiring was letting moisture in and my wire connections were arcing to one another.

[zerokool59]

I had the same problem a while back . it was so bad that my headers lit up bright red . it turned out being two bad fuel injectors . try testing them with a multimeter . it could also very well just be plug wires (cheaper than new injectors so you might give it a shot )