It's a stretch, but...
 

Is there anyone in the Irving area that knows a bit about LS1's and possible diagnosing? I had a few runs against a GTO Wed's night and on the final run my fantastic shifting ability showed itself with a miss shift, went from 3-2 instead of the obvious 4th gear. I'm throwing a P0300 (twice), and a secondary AIR code which I've been having off and on. It shakes horribly (obviously from the random misfire codes), but at medium to wot it clears up, from what I've read/heard that would point to the O2s. When I miss shifted the rear hopped a bit, I threw it into neutral asap as soon as it happened. I think the rearend is fine, I didn't hear any unusual noises, and as far as a ticking or knocking from the eng, I'm hearing something, not exactly sure what I'm hearing though (I.E. pulleys turning etc). I want to try and at least figure out what the problem is, but I have no idea what I'm doing (used to work on toyotas). I'd appreciate any help, yes, I know I'm a dumbass, sorry for the post being so long. Wouldn't be such a big deal if it was my daily.

99 TA, M6 (obviously), stock everything except for an SLP CAI.
Thanks for any help and would appreciate if anyone could come over and help me out

I did this exact thing one time...went 3-4 but kind of pulled the shifter towards myself and in went 2nd...rear end hopped once or twice but never missed a beat...if you have a problem going into 4th flip your hand over as if you were giving a thumbs down when you go to grab 4th...but it was more than likely just a once time deal...now pertaining to your question...I dont know...just figured I would throw that suggestion out there

Just be glad it wasn't a cobra...had a friend do this and popped the center section in the irs...I loled because I was riding with him when it happened

have you checked your plugs and wires? I would check your o2s as well.

My wires seem fine, good connections all around, haven't had time to pull the plugs as its a pain in the ass, and I don't have a jack so its kinda hard to check the o2's. I'm debating taking it to a dealer a friend works at so we can get it in the air, but I'd have to drive it up there.

I would start by checking the plugs, its a PITA but be patient, it will pay off, if its just a $30 fix.

How does downshifting into the wrong gear affect your o2s or wires???

Pull your sparkplugs. Next thing I would check would be valvetrain, pull your valvecovers.

I've been wondering the same thing about the o2s, I do have a pretty good amount of fuel and smoke coming out of the exhaust, I'd imagine thats from the unburnt fuel from the random misfiring

It doesn't affect it, but he's throwing a misfire code and those will be the first things I would check before pulling the valve covers, from own experience I recently had somewhat the same problem and turned out to be that both o2 sensor's wires were completely melted after a few runs at the track.

a misfire will make you run pig rich and black smoke from unburnt fuel.

its not black smoke, from what I could tell with it being pretty dark out and only having a flash light, it was white. It could also be becuase it pretty cold out and I didn't let it really get to operating temp

ouch that will hurt

Exactly what I was gonna say, check for a broken spring, if not broken pushrod. Only takes a few minutes to take the valve covers off.

Hmm. We have had a few customers do that and they bent some pushrods! But I doubt this is the case with yours because it clears up!

Did you over rev it and bend some valves from the float???

I did this same thing back in 99 on my 99 ss, and ended up bending several pushrods. It would make noise, and run rough, but it would clear up when WOT.

I'm willing to bet you bent a few valves from the over rev. Could have gotten lucky and just taken out a few spark plugs. Pull the plugs and do a compression check on each cylinder.

Im going with this one.

me to

We would love to assist you if you want to bring it to the shop. You need to do a leak down test to check for bent valves as well as have the valvetrain checked.

do a compression test and go from there, can you see which cylinder the misfires are on or is it all across the board on the misfire graphic? if so i would definatly do a compression check and figure out if you have good compression, if its on a specific cylinder i would check spark on that cylinder, if spark is good check compression on that cylinder, if compression is good, check injector. dont think you will get that far, but if you think its your 02 sensors, just unplug the engine monitoring 02 sensors and the ecm will default them and the vehicle should clear up, but im gonna agree with dirty30 and others that say its probably bent pushrods.