Ok I give up :(

[blizzardwarrior7]

Ok, i have posted several threads relating to a problem i have been having lately.....Rough idleing, and sometimes the engine just dies during deceleration. I think its only running on 7 cylinders when its idleing, as the rpms are lower than they should be and everyonce in a while it jumps up to where the idle speed should be. When my foot is on the gas it runs fine. What is it? Ive tried adding thicker oil, changed the oil, injector cleaner, all the easy fixes, what else could be causing it? I really dont want to drop any more money into this thing, but I realize Im going to need for it be reliable when I plow with it again next year, and chances are Ill keep putting the repair off.

The thing that made me thing it was oil related was this: The problem only occurs after about 3-5 minutes of driving, or once the engine has had a little time to warm up...

[beerman1]

7.3l have issues with the injector harness's that would be the best bet. look by the valve covers there should be 2 plugs one on each side, they are by the inside edge of the valve covers pull the plugs out and check for any corrosion and or missing contacts...

[bigcountrysg]

When was your last oil change. Have you scan for codes, have you done a buzz test, contribution test.

[blizzardwarrior7]

Alright, Ill check the harnesses, oil change just a few days ago, no codes. No buzz test or cont. tests.

[bigcountrysg]

Originally Posted by blizzardwarrior7

Alright, Ill check the harnesses, oil change just a few days ago, no codes. No buzz test or cont. tests.

You need to scan for codes with a scan tool not a code reader. You also need to have an Injector Buzz Test done, as well as the cylinder contribution test done.

[blizzardwarrior7]

Yea, Ive checked with my code reader and brought it to ford and they scanned it and didnt find anything either. I was hoping it would be a quick fix, ill try the injector harnesses first .

[sldghamr]

one of the biggest clues for the harness is a plume of smoke coming from the vavle cover. once the harness starts to go, usually goes really quick and you will lose that cyclinder.

[tubular031]

Find someone that can do the buzz test for you of get this
AutoEnginuity® - OBD2 Scan Tool - Professional PC and PDA Diagnostics

I bought it but have not bought the ford pack (needed for the diesels... ) I used it on my gas cars and its pretty cool. tells you all kinds of good info about your car.

[hpf350]

Could it be your CMP?

[SCUFFY828]

if ford checked it and it had no codes , if this truck has alot of miles on it , i would guess fuel pressure , if it were a short harness there would be codes and a check engine light ,rule of thmb no codes = fuel delivery problem