For the past few weeks the girlfriend's car (2000 Olds Alero, 2.4L 4cyl/auto, 154K miles) has been behaving somewhat badly--idle seems like it may be lower/shakier than normal, hesitates if you give it less than about half throttle, and sometimes stalls out at low speeds while approaching a traffic light or turning. I don't know if the idle is part of the problem or not though; I looked at the engine run with the hood open and you can see the engine physically shake, and it rocks noticeably when you give it gas, so I presume the motor mounts are shot. As to the hestiation and stalling, the first thing I thought was fuel delivery--going to replace the filter, but could it be an issue with the pump or dirty-clogged injectors? Any other likely/better ideas?

9/29/2009 4:40:23 PM

My mom had one of these and it periodically had problems with fouled plugs that we never quite figured out.

9/29/2009 5:30:56 PM

hesitation and stalling could be a bad MAF

9/29/2009 5:32:58 PM

go the cheap route first and put some gas treatment/fuel injection cleaner in with a full tank after you change out the fuel filter

if it continues, then check MAF like ^ said, and continue with further diagnostics

9/29/2009 6:24:47 PM

Quote :

"go the cheap route first and put some gas treatment/fuel injection cleaner in with a full half tank after you change out the fuel filter "

and do an air filter too.
and plugs.
and take a look at it in the dark to see if you see any arcing from the spark plug wires.

9/29/2009 8:30:28 PM

2.4 doesn't have plug wires. It's one of the Quad engines.

Ten bucks says that the coil housing is bad. This engine should use that damn plastic contraption that fits down over the plugs. There are two standard DIS coils that fit into the housing.

I'd seriously bet good money that the housing is bad or that one of the coils is bad. Replace the housing first, then the coils if the problem doesn't go away. Oh, and the default "replace the plugs" while you're in there.

9/29/2009 9:59:16 PM

looks like I owned all of you niggers

9/30/2009 2:16:27 AM

Thanks for all the ideas...will start with the fuel filter and injector cleaner, then do the coil/housing plugs this weekend, and proceed as necessary.

Extremely stupid question, I know, but I'll ask anyway: because the fuel filter is under the car, I know I'm going to spill while replacing it. My driveway is very sloped so the only level space I have is inside the garage, but there's a gas water heater in there--if I work with the door open, on the side of the garage away from the heater, and the end of the car near the door, am I taking a risk of blowing myself up from the pilot light being too close to the vapor from any fuel that spills? If so I'll need to find an alternate flat location to do the filter.

9/30/2009 10:20:22 AM

Do it in the street.

And skip the fuel filter and injector cleaner for now. If you can see the engine physically shake, then you have a miss. See my earlier post. That will also contribute HEAVILY to the hesitation.

Where you at? I'd be willing to bet a dozen cheezburgers that missing is the problem. Put your hand under the tailpipe and see if you don't feel that chuffing on a regular rhythm...which will indicate you've got a regular miss. Again, see above post.

9/30/2009 10:24:32 AM

Makes sense, especially WRT the shaking. I'll see if I get any indication from the tailpipe also, and may just proceed with the coil housing/coils and do the plugs for good measure. As to where I'm at, work at NCSU (out at the vet school), live in Durham near Southpoint.

9/30/2009 4:14:49 PM

I'm off of Lumley Road near Lakeshore Golf Course (between Page and Miami), if you need somebody to do any work for you.

9/30/2009 4:19:37 PM

So I took it apart and checked everything out--I'm going to have to give a rather unscientific description of things. By coil housing, do you mean the black plastic job with a rubber insert and a metal piece inside, that connects the plugs to the large metal assembly that sits atop the engine? One of those had a small crack in the body but didn't look like it impeded the functionality. None of them looked obviously bad other than that.

At any rate, I replaced the plugs--the leftmost plug was pretty oily when I took it out, so I tried to clean out the socket best I could, then put new plugs in. After putting everything back together it's worse than before--stumbles more seriously than it did, really have to gun it off the line to get it moving, and I've got a CEL activation to top it all off. Bad enough that I'm not willing to drive it to work tomorrow morning (girlfriend is taking my car until I fix hers). Halp?

10/12/2009 12:34:57 AM

The big assembly that bolts to the underside of the metal panel you take off. Plastic and has four towers that go into the spark plug holes. Coils are inside of that.

10/12/2009 12:40:58 AM

you def have a bad coil or have voltage leak from the housing, and a valve cover gasket leak

10/14/2009 9:01:25 AM