I've noticed on occasion that when I start my Bonne, there's a noticeable [forward] lurch of the car. The first time I noticed it I was actually outside the car, using the remote start. It was in my garage and I started it and it lurched slightly and jumped the heck out of me. It didn't actually move forward on the tires, but it was a noticeable lurch forward and then it settled back. It doesn't seem to do it all the time, but when it does, I notice it. Is this the beginning of a motor mount failure, an 'out of gear' adjustment or a tranny issue?

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2005 Bonneville GXP (SOLD), Crimson Red Tintcoat
Other Rides: 2009 Solstice GXP Coupe #606, Cool (Liquid Silver) | 2007 BMW 750Li, Toledo Blue Metallic
Past Rides: 2007 Grand Prix GXP, Red Jewel Tintcoat | 2004 Grand Prix GT2, Fusion Orange | 2002 Bonneville SSEi, Black | 1999 Regal GS, Black | 1997 Bonneville SSE, Blue-Green
1994 Cutlass Supreme S, Turquoise | 1989 Cutlass Supreme IS, Bright Red | 1988 GMC Sierra 1500, Dark Red | 1982 Regal Sport Coupe, Maroon/Silver | 1975 LeSabre, Beige
Wife's Chariot: 2006 Buick Rainier CXL, Red Jewel Tintcoat

IDK, but i'd say since the tires didn't move, that the mounts is about shot!!!

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2005 Bonneville GXP Fully Loaded

Or the normal torsional twist to a transversely mounted engine upon startup where the engine actually starts at a higher RPM than normal upon initial firing as it's in open loop mode.

A broken motor mount he'd notice driving down the road... Probably actually shifting it out of park and into reverse or drive and he'd notice that.

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Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck

U got a point there... I noticed that my GXP does it too!! Oh well, it shifts normal so im not worrying about it..

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2005 Bonneville GXP Fully Loaded

CMNTMXR has a point. It is only noticeable on occasion; I would think a bad mount would always be noticed. I'll still check it but I'm not sure I'd know a bad mm from an ok one. But CM is probably on to it.

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2005 Bonneville GXP (SOLD), Crimson Red Tintcoat
Other Rides: 2009 Solstice GXP Coupe #606, Cool (Liquid Silver) | 2007 BMW 750Li, Toledo Blue Metallic
Past Rides: 2007 Grand Prix GXP, Red Jewel Tintcoat | 2004 Grand Prix GT2, Fusion Orange | 2002 Bonneville SSEi, Black | 1999 Regal GS, Black | 1997 Bonneville SSE, Blue-Green
1994 Cutlass Supreme S, Turquoise | 1989 Cutlass Supreme IS, Bright Red | 1988 GMC Sierra 1500, Dark Red | 1982 Regal Sport Coupe, Maroon/Silver | 1975 LeSabre, Beige
Wife's Chariot: 2006 Buick Rainier CXL, Red Jewel Tintcoat

You would notice a broken mount when you shifted from Park to reverse or drive. You'd get a huge "clunk" (Moreso than normal).

_________________


Retired Bonneville Owner and former GM Tech:
2004 Pontiac Bonneville GXP: Black/Ebony *SOLD*

Summer Toys: Combined 827 RWHP / 877lb/ft RWTQ
2004 Pontiac GTO: Impulse Blue Metallic/Black/M6: lots 'o mods, 415 RWHP / 405lb/ft RWTQ!
2006 Cadillac STS-V: Light Platinum Metallic/Light Gray/A6 - Spectre CAI, Magnaflow exhaust, Speed Inc. tune, 412 RWHP / 472lb/ft RWTQ

Daily Drivers:
2019 Chrysler Pacifica Limited: Mommy's new RGC
2015 Chrysler Town & Country Limited Platinum: Kids new RGC
2007 Chrysler Town & Country Limited: Sold to neighbor
2009 Pontiac G8 GT: L76, Sport Red Metallic
2003 Chevrolet Suburban 2500: Doeskin Tan - 8.1L Big Block... new plow truck
1999 Chevrolet Suburban: Sunset Gold Metallic - Daddy's winter beater and plow truck