Here we go again


#1

(code p.o.302) number 2 cylinder misfiring. 1997 nissian pickup 2.4 liter automatic. when I take truck out on highway check engine light come on with code p.0.302.when I get back to town. and cut truck off for maybe 20 minute. check engine light go off automatic I do not have to use a scan tool to erase.as long as i’am in town light. say off. when I get back on highway check engine light come back on. have had 3 mechanic look at this they can’t get it to misfire. they tell me the fuel and spark are doing what they support to do…do you think maybe computer bad. has 255,000 miles


#2

Have you checked the compression of the #2 cylinder?


#3

Check the distributor cap and ignition rotor for wear.


#4

Distributor cap, rotor, spark plug wires, spark plugs… you’d be amazed at how many misfire problems are fixed by just changing these. When was the last time yours were changed?

If these have all been changed already, you can try changing the #2 injector with one of the other injectors and see if the codes moves with it… or get the injector bench tested… or try changing it. If it does turn out to be a bad injector, change them all. When one goes, the others are sure to follow.


#5

If injector #2 is partially clogged you would expect a lean misfire at high speed/high fuel flow rate, but no misfire at lower speed/lower fuel flow rate, like what you report.

I would do as mountainbike suggests and swap injectors to see if the code follows the injector.


#6

Gotta agree. Computer makes no sense. Plugs, wire, coil, rotor, compression.