Scotty Solve my Misfire Woes...been working on this car a YEAR now!
Alrright, here goes....
The vehicle 2003 Cadillac CTS 3.2, I've had a misfire on 1,3,5. Here's all I've done:
New heads, head gaskets, intake gaskets, coils, injectors, crank sensor, cam sensor, throttle body clean, knock sensors, timing kit, timing belt, cleaned pcv system, new fuel filter, etc...you name it I've replaced it.
Compression Test: 150 psi all cylinders
Cylinder Leak down test: All less than 15%
Timing marks (used install kit to do the job): Dead on, verified many times and TDC is on compression stroke
Spark: Getting fuel and Spark (verified)
The car misfires @ idle and shakes horribly. The codes that the car throws consistently are P300, P301, P303 and P305 and the Check Engine Light Blinks. If I step on the throttle the blinking check engine light goes away @ 1000 rpms and above. Car drives fine, just horrible misfire at idle.
Ran vacuum test and I'm at 15 inches at idle (Late Ign Timing on Gauge) and when I hold it at 2500 rpms no fluctuation goes to about 18 inches and is smooth. I attached the video of my fuel trims via my scanner. Please help me if you can. Any suggestions?