Guys the girl friend just got an '02 Escape with 3.0L V6 and 162k on the clock. The dealer she got it from said they replaced cylinder #4 COP. So the day she bought it the CEL came on, I ran the codes with my cheaper MAC tools scanner and I got code P0304 for cylinder #4 misfire detected. So I tore the cover off and verified that yes the dealer did replace #4 COP. So then what I did was I switched the #4 COP with the #5 COP and replaced #4-6 spark plugs all at the same time. Then I reset the light but after a few drive cycles the CEL will come back on and give me the same P0304 code thinking #4 is still misfiring. Her Escape runs like a champ, has plenty of power, idles smooth, doesn't sound like its missing. The only thing I do not know is if its using gas excessively because I do not drive the thing on a regular basis. What am I to do to get the CEL to go away? I do not understand what could be causing the computer to think #4 is still misfiring. Should I just yank the battery for a little while and let it reprogram itself?

Thanks for the help guys!

Shane
Glynn Motorsports

 

You'd need a ignition scope to determine what the problem is with that cylinder, wiring, injector, valves, etc. A DMM that can read pulse width might catch injector problems.

 

The thing that I do not understand is why it feels like it has no miss nor does it sound like it is missing.

Shane
Glynn Motorsports

 

Depends when it's happening. A miss at idle is easily felt but at 60MPH, nothing.

If you had a scanner that grabs the Freeze Frame Data would tell you how fast you were going and at what RPM when the DTC was set. My scanner will monitor 20 PIDs continuously at a user set interval and then when you press a button it will capture so many interval then stop. You can wait for a event like a CEL, hit the button and you have a before/after capture showing exactly when you hit the button.