LT1 Misfire Issue

[xitmnt95]

So I have replaced literally the entire ignition system on my 1995 Pontiac Trans Am (ICM, Opti, Coil, plugs, and wires) and thing was fine for about a day and a half and then it started missing again. Any ideas on what this could be?

[meissen]

Is it throwing any codes? Are you sure none of the wires are shorting out or arcing?

[xitmnt95]

No codes. I just changed the plugs and wires. About 40 miles on them.

[zeeman]

What brand opti did you put on?

[zeeman]

Do the usual diagnostics, spray the wires down with water, look for arching. Does it run ok at any speed or condition?

[scubasteve90]

Dont rule out o2 sensors either. My car would mis fire and stumble going down the road. Changed out the bad one and it was fine.

[QuickTop]

Dont rule out o2 sensors either. My car would mis fire and stumble going down the road. Changed out the bad one and it was fine.

:X2: on the 02's

[JoeliusZ28]

You can tell if its 02s or not based on if the misfiring begins when the computer engages into closed loop. (if you dont have a scanner the engine stays in open loop during warm up, so it will run fine then).

Also, what brand of spark plug wires and were they cut to length? Brand and model of spark plugs? Gap on the spark plugs?

LT1 ignitions are fussy. New parts doesnt necessarily make everything happy unfortunately, you need the right stuff.