1999 K1500 Z71

At high rpm, about 4.5K-5Kish i get what sounds like rapid backfiring sounds like its coming from underneath the vehicle rather than out of the exhaust. other than that it seems fine. The previous owner apparently did
some mods to the engine. it has a K&N intake, bosch plat +4 plugs and a flow master exhaust. seems to have the factory MAF still installed. dealer said that putting the factory air box back on will fix the prob but others have told me the converters may be gummed. since ive had the vehicle i havent done anything to mod it and normal everyday driving not even a ping. using 89oct. fuel. anyone experience similar or might know a cheaper fix? Thanks for any info provided.
99 Z71 K1500 5.3L extended cab
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Havent you heard that the K&N filters let in MORE dirt to your engine than the standard OEM Filter, You may get more air flow from the K&N but you get less protection from the elements.

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On Tue, 13 Mar 2007 02:12:00 GMT, "AnotherAnonymous"

I think because of its current state I would beg, buy or borrow a real time OBD2 scanner and read engine data in real time to give you a clue as to what is really happening. I have done this myself a few times. I have a few ideas as to what might be wrong but I think I will let the peanut gallery pipe in first. I will tell you this much that the mods are not helping things. That is a closed loop engine tuned from intake to exhaust and when you start hacking, things can happen sometimes and a OBD2 realtime scanner would be the place to start unless you want to chase gremlins for a while that other may have you do. ----------------- TheSnoMan.com
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SnoMan wrote:

Have inadvertently coated the MAF with lovely red K N filter oil?
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