2004 Grand Prix GT - not sure if this is a transmission or engine issue - thought I would start here - I'll move if I need to
When I'm accelerating from a stop the car slams into gear. It feels like it is downshifting hard but that seems weird as it would have to be starting in 2nd...anyway, that's what it feels like. Only happens if I ease onto the accelerator, like I normally would in stop and go city driving. I've gotten to the point where I can almost feel when it's going to happen. I've got tons of examples but here are two. First, if I let off of brake from a stop and give enough gas to get rolling then step on it to even get to 25 mph it will slam into gear. Second, yesterday, I was stopped on on incline, gave it enough gas to inch forward against the grade, then stepped on it to pull into traffic - SLAM. Always after an initial hesitation. Nothing about it feels ok. Been acting up for several weeks now. On the other hand, if I mash the accelerator >25-50%, without hesitation, no problems...but this makes city driving a little awkward... Otherwise, I don't notice any shifting issues at any other time.
Transmission fluid is full and clean. No CEL - so I haven't had any codes pulled. No mods.
Service in last 10K/4months = MAF, MAP sensor, plugs and wires, Tstat, flushed coolant, flushed PS fluid, tranny pan drop, filter change, installed transgo shift kit. Cleaned TB but it might be time to do this again.
Other issues = I have had the ABS/TC problems, replaced hub, no love, then tracked down to the wiring harness and have ordered the part and plan to replace that this week. But that problem and this one don't match up timing wise - but I thought I'd let you know what's going on.
Any ideas where I should start?
