OleStraightStick

Well my car sits in the garage most of the time, & recently when I took her out for a spin, I noticed right away that something wasn't right when I opened her up.. everything runs perfectly fine until it hits around 3500 rpms, then the engine seems to vibrate, sounds a little different (could just be me), & seems to lose power.. I briefly googled ls1 vibe issues but didn't really find anything that matched my symptoms.. I know the ls1 is internally balanced, so does anybody have any idears of where I should start? The CE light has always been on due to unrelated codes, but I'll pull codes again soon and see if there's anything indicative or possibly related..

Btw, it's the engine, not tranny or drivetrain because when I depress the clutch and rev, it still shows the symptoms

chevy406

Sounds like you may have a miss in the engine - likely ignition related. Check your plug wires for looseness or damage. May want to go ahead and replace the plugs and wires. Definitely need to check your codes and see what you can learn from the ECM. If all else fails, bring it up to Huntsville, and I'll help you out.

OleStraightStick

Thanks! I put new plugs & high performance wires on it last summer, but I suppose it's very possible that one of the boots came unsnapped from the plug.. I'll def check that out as well.