Misfiring 90' 302!!!

[broncojoe90]

:-" Hey everyone, i have a 90-'bronco with a 302 efi. Went to inspection today and failed for a blinker i can fix, and also something with the emissions... the guy @ inspection said it might be plugs or timing... I've already changed, plugs, wires, cap, rotor, air filter, idle air control valve, pcv valve and fuel filter. Also bought a timing light today to check timing. 2 quick questions: should i change the 02 sensor?, and with checking the timing, am i going to get a "zap" while turning the distributor cap with the truck running? I've never done this before, and i'm trying to keep the costs down as well. Under the hood said timing should be 10 degrees before top dead center. The truck has been misfiring and need to get this fixed asap. Any tips??? thanx for all your help everyone....

 

[firelt90bronco]

I actually just set the timing from my distributor today. Loosen the 1/2" bolt that holds the distributor in place, turn the truck on and turn the distributor until it sounds like its running perfectly. Turning the distributor counter clockwise will richen the mixture and clockwise will lean it out.

 

[89Bronco58]

no you wont get zapped if your wires are good, but i would wear a glove to be safe, most likely if it is misfiring it isnt just where the timing is set, unless it has been that way since you got the truck, then someone else may have set it wrong, so just start the truck and check it with the light to see where its at, did you buy a degreeable timing light? and yes i would change the O2 sensor, faulty or not, its pretty cheap and could be part of your emmisions problem