Hi guys, real desperate I am supposed to leave for our family vacation and my truck has let me down!


2001 excursion 4x4 limited, 250k. I was towing my trailer 8k up hill when I heard what I thought was the cat rattling pretty good (it was the heat shield on the down pipe) but it did loose some power and started running pretty rough.


Got home, bought all new plugs. The pass rear plug got tossed last year and I had to have a shop install an insert. That plug had melted the electrode when I pulled it out, I am guessing that the thread isn't sealing and is drawing air causing a lean condition.


All other plugs looked worn on the electrodes, scanned it and #5 and #10 cylinder misses detected, injection fine.


I buy 2 new accel coils and install, it is much better (80-85%) but still a little rough at idle and for sure not smooth like before. I checked by spraying some sensor clean around all vacuum hoses and nothing seams to be leaking. Also cleaned the intake sensor and the filter is newer and clean.


Any suggestions I am about to loose my mind!

 

You mentioned that you already scanned the computer, finding a miss in #5/#10 cylinders. Was that after you saw a MIL (check engine light)? Have you scanned it since? Are you getting more misfire alarms?

Consensus on aftermarket coil packs seems to be more installer-psychosomatic than an actual performance increase. Same with special spark plugs.

Aside from scanning for errors, have you replaced the fuel filter lately?

 

Sorry for the late reply, I just finished a 800 mile trip without any difference in how it runs.


Since the first post, I have purchased a decent Innova scanner to monitor and read codes. Before I got my scanner, my friends scanner (a full time Ford mechanic's expensive one) he scanned the fuel system and showed no issues, we were pressed for time and couldn't get too far other than the misfire codes.


I have got misfires on #5 and #10 cylinders. I replaced all plugs and without any change replaced both coils, still no change.


Right before my trip and running low on cash, I did all boots with dialectic grease, did a sea foam treatment and a fuel treatment. It was for sure smoother but still wasn't running on all cylinders like 2 weeks ago smooth.


During the trip another cylinder was cutting in and out and that was #6.


I can read and freeze data, is there a particular parameter I should look at?


I replaced the fuel filter about a year ago, the air filter is 2 oil changes old and clean, and I clean the intake sensor every 3 months or so by removing the intake and spraying the little coils on the sensor.


I also removed the catalytic convertor thinking it was plugged maybe but that was not the case and I will be putting that back in as I cant stand how loud it is with a 2 chamber flowmaster.


Please anyone with any suggestions on how to trouble shoot this issue its got me loosing sleep, the V10 has never missed a beat but now I am wondering if I should have bought that chevy?

 

I did the filter last year, not sure if it is a root cause after all the codes.

 

I know it over a month old, but I would suggest getting new injectors or sending them off to be professionally cleaned and flow tested.

I sent mine off to be cleaned and some worked ok, others were terrible.

Cost about $200, or you could buy some used cleaned ones for about $120.

I suspect you could have a couple poor injectors.

Anytime I buy a used vehicle, this is one of the 1st things I do.

I use witch hunter performance to do my injectors.

 

I had a miss on #5 and did a compression check. Found 0.0 PSI. So I pulled the valve cover and saw the intake rocker arm laying at the bottom.Had a sticky valve due to a bad fuel pressure regulator diaphragm. So I fogged the engine with Sea Foam Spray after replacing the rocker and lifter with new parts. Runs fine for about 400, 500 miles now.