Before I describe whats happening let me say that not too long ago I had an O2 sensor check engine light come up..but then went away about 2 days later.
As of now when traveling on the highway at constant speed my rpms will be at about 2500 and then it will start to jerk and will bump up to 3000 sometimes.
Is that the fuel pump? Should I try some inj. cleaner?
thanks
What can I do to know? I mean i dont think this is something autozone can check..
Well to test a fuel pump you need a fuel pressure tester.
You dont take one sympton you have and toss an expensive part at it
You would need a scan tool to see why the car is jumping/jerking at RPM, you would need to see what the engine sees, and determine what the cause is.
Otherwise you are just a blind man throwing darts
- 2004 Cavalier - 124k, owned since new
what was the original code for the 02 sensor? There are a couple that could be an o2 sensor, or on the other hand could be the cat going bad, restricting exhaust flow and causing your surging. Like the other posters said - you need a scan too with that you can watch live data. There are always at least 2-3 possible causes to explain a symptom.
thanks or the input guys...another thing I just thought about since you said clogged cat, maybe this could have something to do with it.
Anyway, when I turn my car on or at idle sometimes I can hear my muffler or something (maybe cat) making a rattling noise... I think im going to rule out exhaust and O2 and make a muffler shop visit first.
So I still dont know that the issue is. I thought it was some bad fuel being sucked up in the bottom of the tank or something. It went away for a week or more when I ran premium 100% gas from Shell.
But now, even with that gas I noticed it starting to do it. I did a "test" with the fuel pump by holding the brakes hard and giving in the gas to the floor and it didnt buck or kick doing this for about 10 seconds.
So what is next? Could it be the fuel pump still? Coil pack? 85k miles...
It will also jerk letting off the gas sometimes...
I'm going to check for vacuum leaks tomorrow.
Anyone know of what the problem could be?
No offense here man but your "test" did nothing except waste gas.
Like I said above to actually TEST the fuel pump you need a PRESSURE tester, they run about $50, you would need to test at idle, do a snap throttle test, and a 2500 RPM.
Vacuum leaks dont cause jerking/bucking, vacuum leaks cause a high idle, and you usually if you have a good ear can hear a hissing sound. If you had a vacuum pressure gauge about $25, you could see manifold vacuum, it should be about 21HG at idle, but again that isnt your problem.
Bucking/jerking can be caused by so many things within the ignition and fuel system. You would need a decent scan tool tha updates live data fast to view it while the vehicle is acting up.
You might as well just spend $80 and have a shop find out what it is, rather than spend $80 on parts and be in the same place.
just my opinion
- 2004 Cavalier - 124k, owned since new
I was told $40 for a fuel pump pressure test.
Thanks for the info. I'll let yall know what happens.
Im having kinda the same problem. mine only does it when its idleing and it constantly drops rpms. ive been told it needs a throttle body cleaning. any ideas
its a 2002 ecotec
DOPER.
REDECO wrote:Im having kinda the same problem. mine only does it when its idleing and it constantly drops rpms. ive been told it needs a throttle body cleaning. any ideas
its a 2002 ecotec
Try putting in some Seafoam and see if it clears things up.
