Just changed spark plugs to rid my misfire code P0304. Cleared that one but now I'm getting another misfire code in cylinder 2 (P0302). Below is the freeze data I caputured from the OBD II scanner. I cleared and then recaptured the code three times (below) to try and help with the troubleshooting. Can someone school me on interpreting the data? I assuming it's the injector causing the problem. If so, should I buy a new one or have this one cleaned? Or, should I first take it to a shop that can do a motorcraft power injector flush (never done this before and I hate to foul my new plugs, they were B#$%!) to change)? Should I buy a "noid" light to make sure the pluses are all getting to the injector? Just looking for a little helpful advice.

Ken

97 Expedition 5.4 Triton 150,000 miles.

1st, 2nd, and 3rd code captures

DTC that caused freeze frame p0302 p302 p302
engine rpm 642 2499 1962
load value 32.1% 92.5% 62.7%
coolant temp 179deg 201deg 203deg

short term fuel trim1 0.8% 2.3% 4.6%
long term fuel trim1 11.7% 2.3% 0.7%

short term fuel trim2 -3.4% -1.0% 0.8%
long term fuel trim2 6.2% 2.3% 0.0%

short term fuel trim3 8.5% -18.8% -99.3%
long term fuel trim3 -4.6% 80.4% 72.6%

short term fuel trim4 28.9% 24.2% 1.5%
long term fuel trim4 -74.3% 85.9% 57.0%

vehicle speed 0 mph 37mph 22mph

fuel system 1 clsd clsd clsd
fuel system 2 n/a n/a n/a

 

I would try swapping two of the coils and see if the miss moves too.

 

Good idea.. 1 & 2 would be easy enough to swap. I did bench check the resistence of each COP when I had them off but who knows. It may be acting up under pressure. I can feel/hear and see the problem on the tach as soon as it starts so I don't think it' s a heat issue.

The biggest consistent deivations are in the #3 and #4 fuel trims. I'm assuming that's when either the spark stops sparking or the injector is having a problem. Anyone know what the different fuel trim numbers (1,2,3 &4) mean? Are thay related to different RPM's, spray patterns, injector ports, pressure or?
Ken

 

Update..

Swapped #1 and#2.. Problem moved to #1. Purchased an authentic motorcraft DG508 coil from dealer (lots of fake "OEM or "OE" Motorcraft coils being sold online, see below). Anyway, that cleared that problem.

Then... Test drove and got a pending p0303 code. Cleared that code then test drove again to verify. This time got an MIL (check engine light). Now I'm getting a p0304.

Now the plan is to find six new authentic coils at a reasonable price (one was replaced last year before I purchased the vehicle). If anyone know where I can find them at a discount, please let me know.

I purchased a set of the knockoff's about a month ago off eBay. Price was right at $130 for eight with platinum plugs! Returned them.. Wrong plugs (though the guy guaranteed me they would work, he didn't confirm that he would pay for the overhaul if they were too hot or smacked the top of the pistion) and I also didn't like the way the connector hook up on the coil was made. The authenic motorcraft coils have a little step inside the female portion of the connector that allows the rubber in the connector to make a good seal. The knockoff's do not have this.

Glad I have another car to drive in the mean time...

 

Motorcraft has a discount line. My reps never told how to spot them pn, but that one did exsist.