Missing cylinder

[BeatDaSHO]

My car has developed a slight miss from 1000rpms to 2000rpms. I decided to clean all the grounds (DIS, crossover tube, ground strap), replaced coil pack, and replaced plugs. It still happens. The motorcraft plugs had 60,000 miles on them and they were BAD. They were white and the gap had lengthend to .60 (i put them in at .44) . I have tried putting in injector cleaner thinking maybe it has a clogged injector but that hasn't worked. I scanned the codes and occasionally i'll get a bad cylinder but not all the time. The first time it was 1,2, and 5. Then i did it again and it was 2, 5. Then i got 5. Then I got nothing. I replaced the TPS as well today for another issue which was solved. Any ideas guys? I was thinking wires maybe but they are only 60,000 miles old too and the previous ones lasted over 100,000 miles. They are motorcraft. Could the DIS be bad? I noticed that after I did the plugs, I started up the motor and it ran PERFECT! I revved it a few times and it was so smooth. So i let it sit there for a bit. I turned it off and back on and then the miss was back. It is a very slight miss. Hard to explain. Any ideas?

 

[PhysicsSHO]

I have tried putting in injector cleaner thinking maybe it has a clogged injector but that hasn't worked. I scanned the codes and occasionally i'll get a bad cylinder but not all the time. The first time it was 1,2, and 5. Then i did it again and it was 2, 5. Then i got 5. Then I got nothing.

By "scan the codes" you mean the cylinder balance test? Each of the three passes is more stringent. This suggests that cylinder 5 is pretty much dead, 2 is very weak, and 1 is weak. Since these span both banks, one cause may be clogged injectors. I had this.

You can check that those cylinders are genuinely sparking by pulling the plug while the miss is going on, and check the injectors are (at least trying) firing by putting a screwdriver or better yet a mechanic's stethoscope on the injector and listening for the clicking of the mechanism.

Air, spark, and fuel, so if you are confident of spark, and air doesn't seem to be a problem, then fuel. Running some cleaner through there may not help badly clogged injectors (like #5), rather than replace them all you can send them off for proper ultrasonic cleaning baths and flow testing. I had this done for ~$100 a few years ago, but the fellow seems to have left the business. Diesel shops may be able to do this locally.