I haven't had my truck for very long, maybe three weeks now. I noticed there seems to be a lot of engine ping/preignition lately on the highway when under load, or just pressing the pedal a little after constant speed cruise will do it.

I scanned the PCM and found no codes. I run regular fuel, never tried higher octane yet. What can be happening here? It has a K&N replacement panel-type air filter in it. Engine supposedly with 80,000-100,000 miles on it. Temperature at the middle of the gauge.
Thanks for any help.
trinogt

 

might try running some fuel injector cleaner through it. maybe you have some engine deposits that are creating "hot spots" i use sta-bil every so often, its actually cheaper than some injector cleaners and does the same job. ive heard of some useing seafoam to periodically clean out the motor. ive never done it but theres no reason it wouldnt help if you follow the directions.

 

Could be a number of things, but one thing you said sorta stands out & that is that it has a K&N air filter on it & they are known to dirty up the MAF sensor, by passing more dirt & if over oiled will pass that on to dirty up a MAF sensor & that'll mess up it's PID output to the computer & is known to cause preignition "ping"

So I might first pull the MAF sensor & Carefully clean it with a non residual cleaner thats specially formulated for the job, like CRC MAF Sensor Spray Cleaner, as it's fomulated to clean them without damage & without residual deposits which will uncalibrate the MAF sensor.

DON'T touch the sensor with the spray tip, but do remove it, so you can get to it from all sides for cleaning.

BE sure you disconnect the battery before cleaning & if you've driven recently, give the MAF sensors element enough time to cool before cleaning, so you don't thermo shock it with the cold spray cleaner.

If you find the intake air tube is also dirty/oily, clean it & the throttle body area too, if it's fouled up, so the cleaned MAF sensor isn't recontaminated.

As racsan suggested, a good fuel system tidy upper, might not be a bad idea.

Chevron Techron Concentrate Plus, at the on container dose rate it hard to beat, especially at AutoZones two-for-one deal on the 12oz size. It'll tidy up the injectors, intake valves & combustion chamber.

Other things that come to mind are wrong heat range spark plugs, acting out EGR system, vacuum leak & this would include a sticking open PCV valve, combustion chamber carbon deposits, dirty fuel injectors giving a weak squirt, low fuel pressure, bad gas, overheating, exhaust restriction, like maybe a clogged cat, crimped pipe, maybe a screwed up performance chip, or someones messed with the computer with a tuner, dirty air filter, or some combination there-of, are some things that come to mind.

Some thoughts for pondering. Let us know what you find.