Heya! Allrighty, well I've been a long-time lurker, trying to learn and absorb as much as I can. But I'm having trouble I just can't seem to find the solution to.
I'm running a 97 Bonneville SSEi engine, the 3800 series II, supercharged, on a rebuilt tranny from a 98 GTP. It's all wedged in the back of my Fiero. Pretty cool stuff, and I've been driving it problem-free for just over two years.
Last week I got one of those fancy Aeroforce Interceptor scan gauges, which I find very awesome. Checking over everything, and it all looks really good. Except I was counting all sorts of misfires happening on the misfire screen.
So I started troubleshooting, and decided to change my plugs and wires since they probably needed to be done, and I was running plugs that probably weren't the best for my application. I switched over to NKGs TR-55s, gapped at .050. Running really nice 8.8mm wires. I also checked my compression, the lowest reading I saw was about 172psi, the highest about 179, so I think I'm good there. Changed the plugs and wires, and...problem solved! No more misfires, felt like lots of power, probably the best it's ever run!
Or so I thought...I was low on gas today, I have been running 91-octane because the only place in my town that sells 94 was out of business. I'm out of town today, fill up with 94, drive around for a few minutes, and start seeing misfires adding up again!
Cylinder 1 and 2 seem good, but the rest seem to go anywhere between 2 and 8 misfires over the course of a minute that it tracks. It seems to be running nicely, nothing bad there, though I'm noticing a bit more knock when I first get into the gas at all than I was seeing before; I don't notice it sputtering or anything. But I see it in the gauge, and I wasn't before I put the good gas in!
There is no code though, no misfire code being stored, no CEL or anything. I'm kinda lost!! Any suggestions you all might have would be hugely appreciated.
Thanks!
-Paul