so anytime i wash my truck drive threw a puddle or when it rains out i get a very bad misfire which doesnt allow me to go over 3k rpm if im lucky. distributor is dry and the intake is dry. this is something ive been battling for a very long time now i cant seem to figure out what the hell is going on. im beginning to think it may be my o2 sensor. i have an A/F ratio gauge and when this happens it will not light up once it does it seem to go away,. anyone else run into this before? any help would be appreciated.

 

Check spark plug wires with a spray bottle and see if it acts up. Could also just unplug the O2 sensor when this happens and see if anything changes.

 

Condensation getting into the spark plug wires causing the resistence to go in the wire. Get some new OEM plug wires

 

Replace the sparkplug wires. Make sure non of them are touching eachother or anything metal. That could cause the wires to crossfire and get the syptoms that you describe.

 

the wires are nology's plugs are brand new non resisted for the wires, cap and rotor a brand new factorythere is zero water getting on the cap or the wires. if there is its dry by the time i pull over

 

I would be checking all grounds and conectors in your ignition system. I fact all your engine grounds and connections.
An o2 wont cause your engine to miss( there is a limit on the amount the amount the ECM will lean or richen your mixture based on info from your o2 sensor. It will affect your emissions, but not drivability. How are you using an A/F ratio gauge with a narrow band o2 sensor?

 

How is the a/f meter installed? on a seperate O2 sensor or running off of you factory o2 sensor wires? check your connection there. Also a wet tps will cause your symptoms

 

i got it figured it. it had nothing to do with 02 sensor. it was acctually the wriing on the Mass Airflow sensor. i have an extension cord made for it and i had mud built up in it. its the only thing i didnt check and my buddy came over and found it.

 

the reasoning for the extension is my intake is on the passenger side instead of the drivers side. my truck is basically a rats nest of wiring lol but it works well when its running correctly.

 

Glad you figured it out. I had the same problem in my 93, it had an aftermarket header and the o2 was right in front of the cat and the o2 had an exposed wire. Sealed it up so it wouldn't get wet and rerouted the wire so it wasn't getting heated by the exhaust pipes. Seemed to fix it but it fouled my plugs by the time I solved the problem.