PontiacBonnevilleClub.com

hi, happy holidays, New Year, merry Christmas.

slight rocking side to side? at what speed please?
explain this rocking pl.

96 SSEi wrote:hi, happy holidays, New Year, merry Christmas.

slight rocking side to side? at what speed please?
explain this rocking pl.

Happy New Year!

It happens when maintaining constant speed and only after the car really warms up.

So if i drive it for 20 mins from cold start, i'd not experience it but when it gets to temp it starts to jerk very very slightly. It feels like a miss, but a minor one.

It will go away when accelerating. But as soon as i try to cruise on the highway i can feel it. When in park i can feel it slightly too.

No codes.

It has new

coils
ICM
leads
plugs
injectors
FPR

Smoke test showed that there was a very slight vacuum leak at the EGR tube. I will tackle this next.

I am now inclined to think its a drivetrain issue. The shake at idle is gone with new injectors. But at speed when maintaining constant i feel a jerking as if tranny is trying to down and up shift at the same time.
This evening i started hearing a creaking noise coming from the driver side front corner. Cv axle on that side has a slight play left to right. Can a bad cv axle cause this sort of jerking at constant speeds.

Issue resolved. It was the TPS. With a new TPS all is well.

smokingfang wrote:Issue resolved. It was the TPS. With a new TPS all is well.

Hey, glad to hear it!

smokingfang wrote: Still got that bucking when doing constant speed.

I had a "bucking" at constant speed that turned out to be torque converter related. It was having trouble "deciding" when to go into overdrive and would stumble in the moment it tried to engage. The easy way to check is to get up to speed where OD kicks in and then move the gear shift out of OD into drive (3rd gear) to prevent it from trying to shift into OD. If the "bucking/stumble" stops you have your answer....

santacarl wrote:

smokingfang wrote: Still got that bucking when doing constant speed.

I had a "bucking" at constant speed that turned out to be torque converter related. It was having trouble "deciding" when to go into overdrive and would stumble in the moment it tried to engage. The easy way to check is to get up to speed where OD kicks in and then move the gear shift out of OD into drive (3rd gear) to prevent it from trying to shift into OD. If the "bucking/stumble" stops you have your answer....

Hi santacarl,

I had an '02 Bonneville several years back, thus membership in the group. Now I have a 2010 Buick Lucerne with the same 4T65 transmission doing this 4th gear 'bucking'. Constantly, below 2000rpm but above 40mph. Above 2000rpm its perfectly smooth. Doesn't do it in any other gear so I'm thinking torque converter going in and out of lockup. What did yours need done a new lockup solenoid? My last trans filter change was about 60k miles ago, I've read that a plugged filter can cause all sorts of issues I'm hoping its that simple. ATF Oil change was 20k ago and it still looks like a good color. I replaced the TPS because that was an easy one and probably due (166k miles) but it didn't help.

Edit, next day: I did a trans oil filter change (there was 68k miles on the old filter) and fresh Valvoline syn oil and its driving perfectly now! I think the filter was plugged up effecting transmission pressures. I also added a bottle of LubeGard 60902. I tore the old filter apart it was very dark and didn't pass light very well held up to a light. No metal in to to speak of except fine common chips. I have the dual magnet kit so cleaned the magnets off good they were pretty caked with fine particles. I guess that's to be expected at 164k miles!