Car Misfiring

My Alero has been missing for about 2 months now. But, it's an irregular miss, happens ever so often. The car will buck, like say it when you're spinning the tires and then they grab traction and it jerks you back, yeah, that kind of jerk just oposite because the car is losing power.

I have replaced the O2 sensor, that didn't help at all. I then replaced the spark plugs, and for about two weeks the bucking stopped, but the engine light stayed on. But then last Thursday, the light went off, and the day after that the car started bucking again.

The bucking occurs most frequently in 4th gear, although it has occurs sightly in 3rd a couple times. It mostly occurs between 55-70, and 75-90ish. Also, the car will sometimes buck so violently that it causes the transmission to downshift.

I am absolutely stumped. Can anyone offer me any advice? Please?

My car is a '99 with the 3400 and 40,000 miles.

[jamcllw]

Take it to Autozone when the light is on and get the code read. Could be multiple things.

[Redog]

Change your plugs, happened to me

Originally posted by Redog@Feb 28 2006, 11:04 AM
Change your plugs, happened to me

Quoted post

I did change the plugs. It helped for about two weeks, but it's misfiring again.



How much does it cost to get a diagnostic from Autozone?

[misslindseysue]

Could be wires or coil packs. I had a misfire a week or so ago, took it in a cleared the code and it hasn't happened since. Lucky for me, I suppose. My plugs are new, but the wires and coil packs are close to 50,000 miles old.
Autozone will scan a code for free, assuming that you're throwing one. That'll tell you which cylinder is misfiring. If it's just one it's likely a wire. If it's a multiple, chances are it's a coil pack (I think there's two of them? I can never remember - so 3 misfires would point to that). If they're decent employess, which the guys at mine are, they should be able to help you out (or maybe you just have to have a rack like mine for that to apply - but they'll still want to sell you parts).

Hahaha.... Thanks for the advice, misslindseysue.

Check your coil packs. Just pull the wire of the post and look to see what the post looks like. If they are corroded, repace them, i recomend accel coil packs, you can get them at summitracing.com, i love mine.
There are 3 coil packs BTW.
If it is misfiring in only 1 cylinder that dosent mean it isnt the coil pack/s.

Well, I took it to Autozone and they told me that the problem is coming from my camshaft sensor and that the connector is either loose, or the sensor is bad all together... Can anyone point me to where this sensor might be on the 3400?

Originally posted by Nik1128@Mar 1 2006, 06:16 AM
Well, I took it to Autozone and they told me that the problem is coming from my camshaft sensor and that the connector is either loose, or the sensor is bad all together... Can anyone point me to where this sensor might be on the 3400?

Quoted post

Dont listen to those idiots.
All they are good for is reading codes and cashing you out at the register.
Did you look at your coil packs yet? It will take you 5 minutes to check all the packs.

Yeah, I looked at the coil packs, they looked fine.

Autozone said that bank one and back two were missfiring... and the code that came up said something about the cam sensor. You don't think that's the problem?

Originally posted by Nik1128@Mar 1 2006, 02:52 PM
Yeah, I looked at the coil packs, they looked fine.

Autozone said that bank one and back two were missfiring... and the code that came up said something about the cam sensor. You don't think that's the problem?

Quoted post

IC, i thought they where tellin you that off the top of their heads. If the code is being thrown for the cam sensor then yes you need to replace that/clean it. I ussually just replace stuff like that. With our cars im not sure how to replace the cam sensor. Do you have a haynes manual or chilton;s?

[AGT]

Originally posted by Nik1128@Mar 1 2006, 08:52 AM
Yeah, I looked at the coil packs, they looked fine.

Autozone said that bank one and back two were missfiring... and the code that came up said something about the cam sensor. You don't think that's the problem?

Quoted post

I just changed this sensor recently. you will need to remove the power steering resovoir by pulling the upper pulley outta the way (3 bolts). It will be just below that on the engine itself. Look for wire loom in black and the top of the sensor is blue. (2 little hex bolts I think) pull the sucker out and place the new one in. reverse from there.

Sounds easy enough.

All right. Sounds good. Thanks for the help, guys.... Hopefully this will fix my problem.