I have an 00 Scab w/5.4. I had swapped out a coil pack due to failure from moisture. I removed the battery cable while making the repairs. After the computer learned the new settings I've started to hear pinging/detonation, but only when she's cold. It'll last for the first 15-20 min after startup and go away. It's not piston slap either, as it isn't rpm sensitive. It's more prevelant under load and there's nothing at idle. No engine light and I haven't bought a scanner yet. I'm just wondering if anyone has heard of this. It only happens for the first 15-20 min after startup and never again, even under load.

 

detonation is caused from either intake air temperatures being to high which will cause poor air fuel ratio. have u dont the preventative matinance like cleaning EGR port TB flushing injectors? could be spark timing or fuel timing is off somehow. also 5.4L were known for timing chain slap... or rattle at cold starts.

 

The truck has to be driven much longer than the old 5L systems, to fullly learn and set the tables.
I bought my truck from a dealer and thought I made a mistake buying it, from the low throttle response it had.
Took nearly 30 days to come around. The clean up shop takes the battery off while it's being cleaned and running around the dealer lot afterwards and customer test drives are not enought time for the PCM to learn.
Today and with 87 octane, no mods except the air inlet thru the fender to the air filter, the truck is outstanding for an 02 4.6L and pulling 11,000 lbs gross weights.
Point is these PCM systems take a long time to settle in. The truck amazes all who ride in it going to the track.
Know what it feels like to drive my truck after unhooking the trailer and driving away even the next day with it's last self adjustment from trailer pulling 210 miles and all the hills etc. The PCM truely has the ability to shift it's operation on the stock program version I have. I'm sure a tuner would make it even better.

 

I'm thinking about changing the plugs and I'll do the preventative as it's at 77k right now. The PCM should've learned by now, it's been about 3k miles. It's absolutely detonation, I know the sound as I used to tune the timing on my older cars by hand and you'd hear it if you had the timing advanced too far. Thanks for the input I thought it might be the PCM, but figured 3-4k would be enough miles to learn. It was cooler this morning, around 55 and it didn't do it at all. It may be due to the warmer mornings. We'll see, and thank you for the responses.