Ok so I own a 2006 buick lucerne cxl 3.8..I have a hesitate at 5060 mph..once a check engine light code came up had it checked at my local auto zone it was a misfire didn't say where jus through that 300 p code I belive it was..I have changed plugs wires ignition coils ignition control module cam shaft sensor and crank shaft sensor and still the same problem..im lost and tired of just throwing money at this thing can anyone help..???I've had the car for several years it has 195,000 miles on it I keep the oil changed I keep up on Trans flush in which I'm ready to have one done in the next few weeks..

Ok so I own a 2006 buick lucerne cxl 3.8..I have a hesitate at 5060 mph..once a check engine light code came up had it checked at my local auto zone it was a misfire didn't say where jus through that 300 p code I belive it was..I have changed plugs wires ignition coils ignition control module cam shaft sensor and crank shaft sensor and still the same problem..im lost and tired of just throwing money at this thing can anyone help..???I've had the car for several years it has 195,000 miles on it I keep the oil changed I keep up on Trans flush in which I'm ready to have one done in the next few weeks..

Did you throw all these parts at it or did a shop do it?
With all those new parts (if they are good ones) I would think you have either a wiring issue or the engine is having some mechanical issues. Possible broken valve spring or leaky manifold gasket. Need to test before throwing parts at things.

So yes I bought the parts and I have a personal mechanic that does my vehicles maintenance..I don't understand how it only does it at 50/60 mph and when the one time a code came up ot was the p300 code I believe but it was a misfire so guess ill see if anyone else has had this problem and fixed it..Thanks!!

Check the fuel pressure during this event. If the fuel pump is getting weak and/or the fuel filter is getting plugged then misfires can happen.

Merged duplicate threads. Duplicate thread was at https://www.gmforum.com/buick-172/06...lucerne-314696

I've had several fuel pumps go out on me so I knkw its not that ..this problem has been going on for more then 2 years..if it was the fuel pump it would have went out by now..but thanks

Fuel pressure is the next thing I'd check. It'* up to you to check it or not. Low fuel pressure can lead to misfires that only come up during certain driveline loading conditions.

Only at cruise and 50 or 60 sounds like it'* during a lockup event.
Not sure that I've seen a TCC problem cause a misfire but....