P0303 and P0316 2002 Taurus with Duratec

I have a friends 02 Taurus with Duratech engine which has the P0303 and P0316 codes. It also has a very obvious miss when under just about any load and at tip in. The vehicle has 43K on it and has had regular service. I changed the plugs and wires as a matter of course hoping it would resolve the issue. It didn't. In my untrained mind, I thought there to be only 2 other possibilities and that would be coil or injector. Since I didn't have a coil handy and did not want to spend another $80.00 guessing, I decided to swap injectors to see if the miss would follow the suspect injector. It didn't. Is there any way to definitively check a coil? I ohmed across the parrallel primarys and my readings were 10.5, 10.5 and 10.6 Kh. Does the dealer have the ability to pinpoint the problem or will they be thowing parts at it til they find it?

Any help would be appreciated since we're not exactly sitting high financially.:banghead:

as you already know, its misfire on #3 cylinder, and it sounds like a hard misfire. The simple test of the coil is, check for spark, if there's no spark, its the coil since the other side of the coil (#4) is obviously working (no other misfire code)

Otherwise, could be bad injector harness (no signal getting to the injector) bad injector driver in the ECM or a compression problem. You (or a shop) can narrow this down quite easily with simple tools and little know-how, but check the coil for spark first

I bought a new compression gage cuz I couldn't find the other 2 I must have loaned out over the years. Ruled out valves/rings with 180 psi and no leakdown. Since this was an intermittent misfire, it was difficult to detect by pulling the wire and watching the spark (it did spark, but apparently not all the time). I broke down and bought a coil and it fixed it. Thank you for your support and my buddy is now a happy camper, albeit $200.00 poorer. Still I suppose better than a dealer may have charged just to diagnose and replace a coil.

I am having the same issue with my 2002 taurus; 110K miles
Since Nov last year it has had continued misfire issues:
Misfire on cyl 1; replaced all plugs and coil pack, and swapped injectors 1 & 3; cured the problem for about 3 months, then it recurred on cyl 3. replaced the #3 injector, problem not fixed. New plug leads helped a little, but the persistent P0303, P0316 codes remain. Cleaned and checked the EGR valve which seems to work ok. Finally I gave in and took it to Ford dealership. Their diagnostics pointed to intake manifold gaskets - compression ok and they did not fault the EGR valve. They quoted >$650 parts and labor to replace the gaskets and clean the throttle body and wouldn't guarantee the misfire would be cured. I did the job myself for $50 in parts and 2 hours of my time; the gaskets were deteriorated and brittle. It's better, but it's still not fixed - the check engine light went away but the codes are still pending, and I can still feel the misfire.
There does appear to be a significant amount of oil in the intake manifold, the car is using more oil than it ought to and #3 is the closest cylinder to the PCV breather, so the next thing is the PCV valve and I'll replace the rear O2 sensor for good measure (I changed the front one last year).
I'm beginning to think that this is a coincidental wear-out of various components. I've had 8 years of trouble free motoring from this car and I'd hate to have to junk it for this rough idle issue. Any suggestions?

Have you considered a faulty Crankshaft Position (CKP) sensor or associated wiring?

-Rod