97LT1Boy

I tried to just post in another thread, so I wouldn't have to start a new thread for a problem that is as common as a misfire; but since apparently that is frowned upon here, I'll start my own thread.

As for the misfire, it does not appear until driving the car for a few minutes, and it gets progressively worse as you drive it. I thought it was just moisture in the gas since I haven't driven the car in a while, but a bottle of heat didn't change anything. the car ran fine a couple of months ago before I stopped daily driving it. now it starts up fine, but misfires bad under even slight load (the ses light flashes) and at idle you can tell there is a miss. any ideas, I can't afford to play parts roulette.

btw, it has new plugs, wires, coil, opti, pcm, no cats to get plugged, no egr, no AIR, and new o2s.

I am going to hook up my AutoTap later tonight after work and see what it shows, I'll report back what it says if anything useful.

thanks,
nick

T WS6 A

I got the same problem and I cant figure out for the life of me whats causing it to missfire.

az0884

What kind of wires are you using? Try pulling your car into a pitch dark area and look for sparks/arching under the hood. If its arching it should be easy to to see and sometimes hear. If the wires have too much resistance the current could be jumping from the wires and traveling down other wires or into the engine block.

Ive also had optis go bad on me within a week of replacing. Its worth considering looking at even if its been replaced recently. Get it scanned first though.

WhiteThunderZ28

Do you guys have Ethanol at your gas stations? Why I ask. cause it goes bad in 30days

Check your wire harness that goes to the coil and see if its cracked or broke.

Did you do the Coil spacer mod?

Check everything out. Something simple can cause our LTX's to run like crap.

red1984

You might also want to check that the waterpump isn't leaking water on the opti.

Also when you changed the opti did you replace the seals in the timing chain cover? you might have oil leaking inside of the opti.

you might also want to try changing the ICM.

97LT1Boy

Ok, I ran the car yesterday with my AutoTap on it and noticed that the Bank 1 Sensor 2 O2 sensor wasn't changing, it just sits at 445mV the entire time the car is running. I can't imaging it being the O2 sensor already, the damn things are virtually brand new. Everything else on the car looked good still though; the coil is new like I said, there isn't any oil leaking, the waterpump is new so it isn't leaking. I'll try running the car without the O2s hooked up to keep it in open loop and see how it does. The only cylinders really showing a miss were on the same side as the "failing" O2 sensor.

Hopefully that's the only problem,
thanks for the input guys.

Nick