Halters and Jerks

Hi All-

Here's what I've got: 2002 Buick Century, V-6, 4 door, nice car, has 35k on it. I just bought it 6 months ago, and has ran smooth as glass since day one.

Here's the problem: I drove it yesterday and all seemed right with the world. Today, I drove it about 10 miles on suburb streets at max speed of 45 mph. I noticed that at about 35-37 mph it was having a very difficult time maintaining steady speed. It was halting, jerking, whatever. But if I got it where it wasn't between gear speeds, it ran fine. Well, I got to where I was going fine enough.

Then, on the way home, it got decidedly worse. Now, I was having issues with the halting at about 25 mph and 35 mph. I was also starting to get some hard shifts as I accelerated through the gears. I babied it to the nearest auto shop 'cuz the check engine light came on.

They said that 4 tranny codes came up (sorry, don't have them) and that I needed to get to a tranny shop. So, I did less than 15 mph about 2 miles mostly downhill to the the tranny shop (got a good cussing along the way!).

They're going to do the full diagnostic in the morning, but I'm very antsy and was hoping that this is something that somebody has seen before and can give me an idea tonight what the problem is.

Thanks a ton!

 

it is possibly just a computer screw up. Not sure where it is on your car but there is a plug under the hood connected to the computer that you can unplug. Any mechanic worth his salt will unplug it for you & say "Have a nice day". For some reason it affects the points where & when your tranny changes gears. If you are light on the pedal at these shift points it will jockey back & forth between gears & drive you positively nuts. If it is this then there is absolutely no reason to spend money at the tranny shop.

 

Could be a number of problems.

Good be a problem with the PCM (modules)

Solenoids on valve body

torque converter

tranny itself.

 

Hi, I have the same issue here with my 98 buick century. I also, noticed that it has these issues when it rains or is very moist outside. It completely stopped starting at one point and so I figured that it was the ignition coil pack. I replaced one coil and the problem disappeared. But now its happening again and so I will attempt to swap all coil packs.

 

Update:

First, DoItOurself, you misunderstood. The car starts fine.

* Well, the tranny was replaced about a month and a half ago with a refurbished one.
* About two weeks later, it started up to it's old tricks again. The tranny shop found a code in the computer that was logged before the replacement. They thought maybe the computer was "remembering" an old problem. So, they cleared the code in hopes that all would be well.
* It ran mostly fine for a week, then started right back with the hard shifting. I couldn't take it to the tranny shop because it was going in to another shop to get the hail storm dings out. I got it back after two weeks of sitting mostly idle.
* The first few days, it ran like a charm again. I actually was fooling myself that the idle time had done the trick. Now, it's right back to hard shifting, but you never know when you start the car whether it's going to be hard shifting or really hard shifting, if you know what I mean. It searches between 1st and 2nd for a long time.

What a mess!! It's going back to the tranny shop tomorrow (?), but I wanted to see if this new input (and new tranny) helps with a diagnosis.

Thanks!

 

Well, there is no doubt a fluid pressure issue in the trans. Sounds like, as stated, to be a pressure control solenoid problem, but there could very well be something else going on here, maybe some debris in the valve body. It isn't unheard of to have a refurbed trans to have issues, we see it happen.

Them trans guys now their stuff, they find the problem. Let us know what they find.