RC000E

My gf's daily is a 2009 LS3 6spd. Been battling some crazy knock/hesitation. I have been running scans like crazy, no engine lights, but it's knocking in most cylinders and pulling a lot of timing. It isn't throwing knock codes though, just a lot of random knock happening and you can feel the hesitation. Happening at small throttle openings...40%-50%, 2k-3k rpm...nothing crazy, just starts flooding with knock. O2's are working and switching fine, no obvious anomalies in the scans at all.

Clearly there are a myriad of possibilities and paths from here...I've been pretty thorough checking out a lot of systems, all maintenance is good (new battery, plugs, wires), MAF looks good, no intake leaks I can find, throttle body is cleaned recently (was having some P2135/P1516 issues for stint, but this issue predated that). Car has 134k on it and rises 75 per day because my gf commutes in it.

Lookin for any past experiences or ideas shy of "check everything"....that's what I'm going to continue doing. Just seeing what ideas or experiences might be out there.

LLLosingit

iTrader: (4)

Has it been doing it longer than a tank of gas? Bad gas could be the culprit.

RC000E

Way longer

I have a SLIGHT inkling that this somehow has to do with the throttle body being out of position to what is commanded, and somehow a deviance in fueling or spark is occurring. I cycled the throttle body and in the 20%-30% opening range there is an audible click and a bit of what feels like "slop" in the throttle plate...like there is a gear issue inside the actuator. I don't have a throttle body for comparison to hear though.

Somethin happenin...gotta keep thinkin...lol

Luke19901

a plug lead breaking with high resistance can cause knock as can a vacuum leak