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MY F350 HAS 69000 MILES AND HAS DEVELOPED A SPARK KNOCK THAT THE DEA
-LER CANNOT FIX , ANY ADVICE !!! NEXT WILL A COMPUTER CHIP FIX THE
PROBLEM AND GIVE ME MORE POWER??
I don't think a computer chip will "fix" any problem. In fact, it may actually make the pinging worse because that is how a chip makes most of the power- by advancing the timing.
We'll need some more info like:
When did the knock start?
Is it the same all the time?
Are you getting fuel from the same station every time you fill up?
Have you tried a higher octane fuel? If so, did the knock go away?
Finally, if you dealership can't or won't help, find a shop that will. Since it appears that you are out of warranty, I suggest finding a reputable independent shop.
Sounds like you've tried all of the standard things with no luck. I'm assuming it hasn't always knocked- correct? Can you tell us what (if anything) the shops have tried?
You mention that it occurs at certain speeds, but have you noticed it at a specific RPM or small range of RPMs?
You may have carbon buildup in the engine.There are products that may help,Thechron by Chevron fuel additive comes to mind.You add it to your fuel per.directions.
General Motors had some carbon deposit remover a few years ago,they probably still do,that you add through the throttle body and it was reported to do an excellent job.
I hate to say it,but you may want to call a GM dealership about this product and see if you can use it on your Ford if it is still available.
THEY HAVE RESET THE PCM TWICE THEN REPLACED THE
PCM. THEN THEY CLEANED THE FUEL INJECTION,
REPLACED ONE COIL, CHANGED THE FUEL FILTER ,
AND SAID THEY CHANGED THE TIMING IN THE COMPUTER?
HERE IS A QUESTION FOR YOU ,THE FUEL FILTER WAS
PRETTY STOPPED UP COULD IT HAVE MESSED UP THE
FUEL PUMP? I KNOW ITS A SHOT IN THE DARK,BUT I
DONT KNOW IF THEY DID A FUEL PRESSURE CHECK OR
NOT. ANY IDEAS ???
COUNTER
Boy you sure have a tough one. I'm not sure how low fuel pressure could cause pre-detonation (spark knock), but I've learned that just about anything is possible. Did you get a chance to check the RPMs when the knock occurs?
I'm really starting to think that your truck has "flutter"... that was the reason I asked about the RPMs. Flutter is a V10 exhaust noise that most commonly occurs in the RPM range that you stated. It sounds like a rattle or even pre-detonation (spark knock) and is caused by the oddly-shaped design of the Y-pipe from the manifolds to the catalytic converter. I've heard of one or two cases where the truck "developed" flutter over a period of time even though most everyone notices it pretty quickly. In 2001, Ford redesigned the Y-pipe to greatly reduce the noise. The only real "fix" has been to replace the manifolds and Y-pipe with an aftermarket header kit such as Banks or Borla.
If your truck is EGR equipped then it sounds like the EGR passage is plugged up. This is a common problem with the 4.6L and the 5.4L. It happens earlier with the use of low quality fuels.