Okhere is the situation, when I bought my car a few weeks agoit had a code for bad cam/crank sensors (11 i think it was with the key dance) so I replaced both of them just to be safe and the code went away. Now that i have that fixed I have p0304 and p0300. I have checked the spark and it is getting good spark, I swapped the plug with a different one. I cleared the codes and they came right back after a few minutes of running. So I checked to make sure the injector isworking and it has its tick. I also checked the resistance of the plug wire and I also tried swapping the wire from a different cylinderjust to make sure that it is not the wire. The only other thing I can think of is the injector is not passing fuel. Also when I pulled the plug in cylinder 4 it had a white deposit on it, not the blistery white like an overheated plug, more like the carbon buildbut white instead of black. So before I go and change the injector is there anything else I can check? Also does anyone know of an easy whay to change the injectors? By the way I have a 96with a 2.0. One other thing i forgot to mention is when I pull the plug wire while it is running the idle does not change, it arcs on the valve cover as i pull it out but no change in idle speed or quality.

 

I would say the cylinder head may need to come off. P0300 is a multi misfire and P0304 is number 4 misfire. So you may have a valve problem with number 4.

 

I had the same problem just after I changed my fuel filter. I just lived with it for a few days, and it went away all on its own. It's been several months and no such code since.

 

Well a new update, I still have the same codes but I did a compression test and cylinder 1,2, and 4 are all at about 200 give or take a few but 3 is at 90. I added a little oil to the cylinder and I went upto 180 so I am going to guess that it needs rings for some reason.