My 02 3.5 seems to feel significantly weaker off the line and throughout the lower part of the rev band than it used to. It still feels fine above 4k RPM, but anywhere else, it seems to struggle to get up and going. Transmission is shifting fine. Off the line, it doesn't want to spin tires. At highway speed, I almost always need a downshift now to accelerate. No DTC's or misfires.
This did seems to occur after a CKP sensor replacement, but not directly after. I'm wondering if the new sensor has an issue or if the relearn was ineffective. Or perhaps its a fuel/air/spark issue?? I'm planning to replace the plugs (96k miles, I think they are original, but they don't look too bad), but should I replace MAF as well? It does tend to pull long term fuel trim back pretty hard (-10-11% during mild acceleration). My only reference point for LTFT is my 01 Intrigue which has over 200k miles, but it stays within a few % of 0.
2001 Intrigue GLS - 208k miles, lunchtime runs only 2002 Aurora 3.5 - 110k miles, daily driver 2002 Aurora 4.0 - 141k miles, not long for this world
Other cars currently in my fleet: 2003 Impala LS (3800), 2005 Yukon XL (5.3), 2017 Chevy SS (6.2 w/6spd), and 2013 Audi A8 4.0
Former cars (i.e. leases that went back): 2007 Hummer H3 (5spd), 2012 Chevy Volt, 2014 Camaro SS (6spd), and 2015 Terrain SLT V6
Totaled: 2008 STS (Northstar) (slid on ice into a tree at 55mph)