I just tried the wd40 thing all over the intake manifold...no changes in idle or the way the engine was running. I labeled the cylinders 1234 left to right...cylinder 1 is on the passenger side and cylinder 4 is on the driverside.

when i swapped the injectors, cylinder 4s injector didnt have the play in it anymore, but it didnt fix the misfire. I swapped cylinder 3 and 4 injector and the mis fire stayed on cylinder 4. any more ideas? I only drive this car 2 to 3 times a week to work....the other days I used my 2012 mustang gt...so i'm not ultra concerned about this problem...I would like to get it squared away if possible though. thanks. I'm in central jersey if anyone is local and are good with these cars.

 

Are you using Saturn or NGK replacement plugs? Dirty coil tower?

 

ngk cooper replacements i believe...coil towers are fine..I swapped the coils and the mis-fire stayed in the same place.

 

Have you taken an old spark plug, plug the sparkplug wire from the #4 cylinder on it and lay it on the engine, then have someone crank it to see if there is spark? It helps to isolate whether the problem is spark, fuel or compression.

 

it doesnt misfire consistently...its intermitten....so I believe its getting spark.

 

The problem with a statement like this is believing is not verifying.
Your original symptom description seemed to indicate that once the engine was started it ran fine until you accelerated through the gears up through 3rd to about 3 or 4 thousand rpm and it would quit on the #4 cylinder. And would not start firing until such time you turned the engine off and re-started it.

A rather odd symptom to say the least but that is as you described it.
Something of this nature to me anyway has tendency to point at something electrical.
That is not totally dis-proven at this point in time.
Unfortunately to totally prove or dis-prove is either going to be through something electrical replaced with a known good part or discovering a bad one.
The lean appearing condition of the spark plug has a tendency to point at a fuel mixture problem.
Unfortunately that has not been proven either.
Moving injectors around certainly was a positive move. If it was an injector problem that should have moved the symptom around and it did not.
While the injectors are electrically driven I can not think of an electrical problem that would effect the operation of one in the manner you are describing.
And as I use Champion spark plugs with no problem I can not think of a spark plug problem that should affect things as you are using factory recommend spark plugs I think from your writing which sort of points back at some form of an ignition problem.
Which is going to be tough to prove un-less you can verify when in the failure mode this is spark or not.
As you indicate you can force the failure mode than you need to be able that there is or is not spark when the miss starts to take place.
It is not practical I think to try to plug into the spark plug cable of the offending cylinder a spare spark plug and then hold that thing next to the engine block to visually observe the spark or lack of it as the engine is running at the time and plugging one in would give you a shock. While I have done it myself that way it will make your eyes light up.
But
At least you will be able to verify that there is a spark or not.
You don't need a spark plug, a screw driver shaft will work too. And a set of heavy rubber gloves would not hurt either.
You might even have a problem with the spark plug wire.
Dunno. Can't see or touch it from where I am sitting.
If it were mine I would measure the compression and see if that is more or less normal on the offending cylinder.
I would use an ohm meter and measure the resistance of the spark plug wire itself the rule of thumb of about 10,000 ohms per foot to see what it measured out as.
And if nothing positive showed up I would try to verify one way or another the existence of a spark when in the failure mode.
None of which explains the lean appearance of the plug.

 

I'm sure the coils are fine, this engine uses a lost spark ignition so if a coil is bad, then two cylinders will misfire. If you did not swap the spark plug wires, then it can still be an ignition problem.

The injectors get power from the buss and ground from the computer. You may have swapped the injector itself, but you still had to plug in the #4 injector connector into whatever injector is occupying that space. The issue could be in the wiring harness to that injector. It could even be a bad ECM.

 

Re reading your first post where the connector to the fuel injector was half unplugged. Look at that connector very carefully. Are there any cracks in it anywhere? Are the pins good and clean, if they are sockets that will be harder to tell. Do the wires look good.

If they are pins, you can use a Qtip soaked in alcohol to clean them. Be sure to use 91% alcohol but if you can get the 99+% stuff at an electronics store, that would be better. If the connector has sockets, then you pretty much have to use a spray contact cleaner, which you can use on pins as well. MAF sensor cleaner sold at autoparts stores is a contact cleaner so you can use it if you want.

Make sure the connector seats firmly against the socket on the injector and the latching mechanism clips into place.

 

If you don't have an electronics store nearby --> pick up a 1/2 pint of EverClear at your local liquor store .......

 

would a noid light be of use here in confirming if the injector power and pulse signals are STAYING in contact with the injector of the offending cylinder? To Keith's point, if it is an electrical issue between the PCM and the injector, the noid light test should verify if there is any intermittency. you can hand rev the car from under the hood and have a buddy tell you when you are at the rpms which seem to trigger the problem.