Slight jerking up hill

[Tink]

So I got the car on Friday. It was a one owner, kept in garage, regular service....etc. 120 K Miles.

Last night, driving home from work , I was taking the freeway. I got it up to 70 and was cruising on home. Slowed down to 60 when I hit some traffic and I just coasted there when I noticed a slight jerk. I looked over at the RPM's to see what was going on and went back to 60. What I noticed is when I get it right at 60 and let it coast there at 2K RPM, It will jerk ever so slightly, and the RPM's will jump. Not constant, just intermittent. It does it when going up hills as well, a little more constant.

I can't describe it any better. I drove it out last night again trying to replicate the conditions since my brother couldn't get it to do it. I took him with me and drove it down the freeway and got it to the right spot where it did it again. Just a little weaker of a jerk than before.

Questions: What the hell is going on with this? I think it's probably one of three things. First, low octane gas. I went cheap for my first fill up. I was going to grab some octane boost at Auto Zone , but thought I'd ask first. I lurk here. Second, plugs, wires general tune up issue. Third, coil packs gone bad. I know aleros tend to have this problem.

What do you guys think? Since I just got it last week, I can take it back to the dealer and throw a fit. I had it in once on friday for a minor annoyance that they fixed. I don't think they've ever seen a woman throw a fit like me, who knew what they were talking about when it came to service and technical issues of a vehicle.

Thanks in advance

Theresa

Edited June 7, 2007 by Tink

[Oracle of Delphi]

So I got the car on Friday. It was a one owner, kept in garage, regular service....etc. 120 K Miles.

Last night, driving home from work , I was taking the freeway. I got it up to 70 and was cruising on home. Slowed down to 60 when I hit some traffic and I just coasted there when I noticed a slight jerk. I looked over at the RPM's to see what was going on and went back to 60. What I noticed is when I get it right at 60 and let it coast there at 2K RPM, It will jerk ever so slightly, and the RPM's will jump. Not constant, just intermittent. It does it when going up hills as well, a little more constant.

I can't describe it any better. I drove it out last night again trying to replicate the conditions since my brother couldn't get it to do it. I took him with me and drove it down the freeway and got it to the right spot where it did it again. Just a little weaker of a jerk than before.

Questions: What the hell is going on with this? I think it's probably one of three things. First, low octane gas. I went cheap for my first fill up. I was going to grab some octane boost at Auto Zone , but thought I'd ask first. I lurk here. Second, plugs, wires general tune up issue. Third, coil packs gone bad. I know aleros tend to have this problem.

What do you guys think? Since I just got it last week, I can take it back to the dealer and throw a fit. I had it in once on friday for a minor annoyance that they fixed. I don't think they've ever seen a woman throw a fit like me, who knew what they were talking about when it came to service and technical issues of a vehicle.

Thanks in advance

Theresa

Welcome to C&G Theresa,

My advice is take it back to the dealer and have one of the service techs take a ride with you and show him what it is doing. Don't throw a fit though, just be calm and explain your issue.

Edited June 7, 2007 by Pontiac Custom-S

[Tink]

I am calling three guy at 3 when he gets in. I just wanted some kind of idea as to what to tell him it was doing. If it's a coil they can do that while I sit in the waiting room.

Thanks for the fast reply and thank you for the welcome.

[Oracle of Delphi]

I am calling three guy at 3 when he gets in. I just wanted some kind of idea as to what to tell him it was doing. If it's a coil they can do that while I sit in the waiting room.

Thanks for the fast reply and thank you for the welcome.

Just tell him/her it's jerking slightly at a certain speed and and you would like a tech to ride along with you to diagnose the issue.

And you're welcome!

Edited June 7, 2007 by Pontiac Custom-S

[daves87rs]

That's a nice looking car there...

I'd go with either the bad gas, or the coil pack. Though I'm leaning more toward the gas...that seems to make cars do some strange things...

Besides, a good cleaning couldn't hurt anyways...

[Tink]

Strangely enough, we couldn't get it to duplicate with the tech in the car. and it started again today. After a new tank of gas. I'm going to run a system cleaner through it. I'm leaning towards bad gas myself. My cousin thinks it's the tranny but honestly I do not. I go past 70 and no jerks at all...just the little hiccups I mentioned.

And she's a beauty isn't she? I really love this car. Nice way to treat myself for getting a great job!

[76ChevyTrucker]

Possibly an issue with the fuel filter also, for no more tha $15 for the filter, it'd be a good investment even if its NOT the problem. Also with 120,000 miles on the engine, its likely that it has possibly seen its first tune up, so you might be able to get away without doing it. Although, I've regularly seen the AC Delco Platinum plugs that are in that engine go for almost 150,000 before they start seriously fouling out on you. If it were me, without any prior service history for the car, I'd start with the basics, fuel, air, and oil filters, followed by plugs and COP boots, after that probably a transmission filter and fluid change wouldn't be a bad idea. From there you could move into more serious procedures and checks if the problem persists.

[Tink]

Update:

Jerking is now happening at 40 MPH and just during normal straight driving.

Coils packs looking more and more like the problem. I have an appointment to take it in next thursday. I like to tell the guys at service what I think the issue is so they don't overlook it. I get nervous about things like that.

[Oracle of Delphi]

Update:

Jerking is now happening at 40 MPH and just during normal straight driving.

Coils packs looking more and more like the problem. I have an appointment to take it in next thursday. I like to tell the guys at service what I think the issue is so they don't overlook it. I get nervous about things like that.

Don't be nervous, remember the squeaky wheel gets the oil.