Ok so Im drivin my 04 ranger for a little while now cause the mpgs and Im runnin low on $$. Startin yesterday, it felt awful funny in the lower rpms, I took it up to autozone to check for codes and he said the 3rd cylinder was misfiring at 1000 rpms. Any idea on what would cause this. It doesnt do it after you get over 1600 rpms or so. Its a 3.0l v6.
Does that engine have plug wires or is it a coil on plug setup? If it is coil on plug system, check just that #3 cylinder. You could swap the coil to another cylinder and see if you get the same error code. #3 spark plug condition? Take out #3 spark plug, check it. Anode and electrode in good condition? Heavy carbon build up, oily? If it's a plug wire to EDIS spark pack system, is the #3 plug wire in good condition, cracked, heat burned? Maybe the wire isn't making a good solid connection at either the spark plug or the EDIS coil pack.
It uses spark plug wires and the edis spark system(if thats what that little box the wires go to is called). I just went out and checked the plug wire and I couldnt see/feel any thing really wrong with it except for normal wear and it was seated good on both the sparkplug and the output box. Anything else that would cause it to do this or is that most likely gonna be it? Ill probly change the plugs and wires all the way around tomorrow cause it could use it anyway. Hopefully thatll fix it
Engine Misfire Diagnosis A dirty or partial clogged fuel injector could cause misfiring problems. Be sure to "read" the plug from #3, this will give you a good idea of what is going on internally with that cylinder. On my 3.0 there were different plugs on the passenger side of the engine than on the drivers side when they were the original spark plugs. Got into a long argument with the parts dept at Ford about the correct spark plug. Parts dude at Ford dealership tried to sell me plugs for a 4.6 saying it was a better spark plug. On the EDIS one side of the engine has a platinum electrode and the other side has a platinum anode. There are different opinions on what type of plug to replace them with. Now Ford doesn't make the Double Platinum plugs anymore they have SP432, AGSF22PP and AGSF12PP. The 22's are a hotter plug than original. Next time I replace them it will be the 12's.
Well I changed the sparkplugs and wires and disconnected the battery so the computer would reset. The cel is off now but it still feels like its misfiring. Any other ideas on what it could be?
http://www.aa1car.com/library/misfire.htm "What causes a cylinder to misfire? Basically, it's one of three things: loss of spark; the air/fuel mixture is too far out of balance to ignite; or loss of compression. Loss of spark includes anything that prevents coil voltage from jumping the electrode gap at the end of the spark plug. Causes include worn, fouled or damaged spark plugs, bad spark plug wires or even a cracked distributor cap. A weak coil or excessive rotor gas inside a distributor would affect all cylinders, not just a single cylinder. "Lean misfire" can occur when the air/fuel mixture is too lean (not enough gasoline in the mixture) to burn. This can be caused by a dirty, clogged or inoperative fuel injector; air leaks; or low fuel pressure because of a weak pump, restricted filter or leaky pressure regulator. Low fuel pressure would affect all cylinders rather than an individual cylinder, as would most air leaks. A leaky EGR valve can also have the same effect as an air leak. In fact, if a vehicle has one or more misfire codes (P030X) and a P0401 EGR code, the fault is likely carbon buildup under the EGR valve. Loss of compression means the cylinder loses most of its air/fuel mixture before it can be ignited. The most likely causes here are a leaky (burned) exhaust valve or a blown head gasket. If two adjacent cylinders are misfiring, it's likely the head gasket between them has failed. Also, if an engine is overheating or losing coolant, it's likely the head gasket is the culprit."
