Engine Vibration

[benp98]

I was wondering if someone could offer some advice.

History: I recently purchased a 2005 Buick ParkAve Ultra with just over 156k miles. It was shifting a bit erratic so I took it to a well renowned transmission shop and they rebuilt it due to the computer detecting excessively long shift times. (I forget the actual code but I confirmed that this is apparently common in these transmissions.) Anyway, I believe this problem has been resolved.
Issue: Afterward I noticed an Engine vibration and took it back to the shop where they loosened the engine mounts to "let it settle" but this didn't change anything. Now I believe the vibration was there before but I chalked it up to the transmission (I only had the car about a week from purchasing it to having the transmission rebuilt.) The vibration is noticeable while driving or just revving the engine in park from about 1600-2400 rpm. I tried to isolate this further and removed both belts, yet the vibration is still there. As far as I know, I have no leaks (I haven't had the car long enough to know if it does consume any oil/coolant but nothing has been concerning in that regards at this point.) I replaced the plugs but this didn't make any difference and the SES light is not on.

Possibilities: I've been told that this could be a harmonic balancer issue, but from what I've read, this was a problem more common to the older cars in the '90s. I haven't checked mine yet and I don't hear any concerning engine noises. At idle it runs very nice and it has plenty of power while driving. Any other thoughts out there?

Thanks!

 

[journeyforce]

Ah DTC P1811. This is a well known code and it because the PCS (Pressure Control Solenoid) is starting to take a dump. I imagine by shifting erratic, you were driving in start and stop traffic or in the city with many traffic lights and all of a sudden after the car was warmed up it started to bang or was very rough shifting into 2nd,3rd and 4th gears? Some have used seafoam and a shift kit to clean up the PCS and to allow better shifts.

I assume by engine vibration, you mean you can feel bumps or shudders in the drivers seat? Open the hood and look through the gap at the bottom while you are in the drivers seat or better yet have a helper sit in the car while you look at the engine. Have him or her put it in reverse then neutral then drive and repeat many times. If the engine looks like it is trying to roll over or shakes while doing that then look at your motor and trans mounts for a bad one. If it only does it while driving then look at your spark plugs and wires as the possible problem especially if they have not been changed in a long time(original from the factory wires had the cylinder numbers on them)

Good luck

 

[benp98]

Yes, that was the transmission code and yes, after the car warmed up, some times it would shift pretty hard in every gear. Since the rebuild, I haven't experienced this. Thank you for the information, especially about the plug wires. When I replaced the plugs I figured that they were the original based on the amount of rust on them. I should have changed the wires while I was at it. I'll give your suggestion a try on the motor mounts.

 

[dcraig1000]

hes already stated that the mounts were looked at and the plugs were changed.

 

[coyotekiller73]

Something else to look at if its a vibration in certain range its a very good possibility your cv joint is going out. When mine started going out it would shake really bad between 40-60. Easy job to do yourself if you wanted. It's common for them to go out if the motormounts are bad and driven on for a long time and given your grant problem, that could have helped the issue. The engine Mainly check for grease build up around the boots of the cv joints, inner and outer.

 

[Cadillac_AL]

It's been my experience that GM OBD II cars do a pretty good job of detecting misfires and usually set a code fairly quickly. Since you have no cel I think the ignition is ok at this point but Buicks are known to be sensitive to bad plug wires and it's always nice to rule them out with new high quality replacements.

I'm sure the harmonic balancers are no more robust than in the 90's but they usually will knock and not really cause a vibration.

So what would make it run rough or vibrate in park and not set a code? hmmm, I would lean toward uneven fuel distribution; possibly from a dirty or malfunctioning fuel injector or two. I would try running some Techron in a tank of fuel and hope for the best.