98 sw2

[xdanx25]

the car runs fine but after it warms up it bogs and acts like its going to die, when u go from a dead stop or if you're driving along and let of the pedal and lightly put ur foot on it it will bog. no engine light is on.

[Ruley73]

Originally Posted by xdanx25

the car runs fine but after it warms up it bogs and acts like its going to die, when u go from a dead stop or if you're driving along and let of the pedal and lightly put ur foot on it it will bog. no engine light is on.

Check and/or replace the Engine Coolant Temperature Sensor (ECTS). It is cheap (<$15), has a near 100% failure rate (factory-installed plastic sensor cracks/breaks), can cause the symptoms you are experiencing, and usually doesn't trigger the SES light. It should take no more than 15 minutes to install if you have the slightest bit of mechanical aptitude.

The sensor is located on the driver's side of the cylinder head and has a two-wire plug going to it.

Another possible cause is a bad/sticking EGR valve, but this usually (but not always) triggers the SES light.

[xdanx25]

Before I check the temp sensor- I'd like to give a more detailed description of the symptom- and there's only one. Before the temp gauge comes up, the accelerator operates smoothly. As soon as it rises, about 1/5th of the gauge, what happens is, whenever the accelerator pedal is depressed from foot-off-the-pedal to just past the slightest foot pressure, there is a short stall. I can stuff my foot into it, and it will get past that bog and jump forward. I can feather the pedal and make a series of mini-stalls, if I try to hold the pedal in just the exact stall position. This occurs at any speed. Take foot off pedal, the depress it just a bit past slightly, and I get a 'cough'- like a quick buck. It doesn't repeat it, unless I let off the accelerator again, and move it past that sensitive position. If the car is under load, like, I'm headed uphill, at a stop, or if the air is on, then, I MUST press the pedal past this problem position smartly, or else the bog kicks hard enough to stall the engine., from idling.
Now, this only happens when the pedal is pushed down, never when it is released. But what triggers the quick buck, or stall, is the position of the accelerator. I've checked the vacuum, replaced the wires and plugs, cleaned out any carbon build up. I had a scope hooked up, and it threw a code from memory, just said,'stall detected', but no more detail.

If this doesn't change your thoughts about the temp sensor, I'll go right out and change it. Because it seems to be related to the temp, it makes sense, but I wanted to give more specific data, in case this is some oddity you've seen before.

[Ruley73]

Originally Posted by xdanx25

Before I check the temp sensor- I'd like to give a more detailed description of the symptom- and there's only one. Before the temp gauge comes up, the accelerator operates smoothly. As soon as it rises, about 1/5th of the gauge, what happens is, whenever the accelerator pedal is depressed from foot-off-the-pedal to just past the slightest foot pressure, there is a short stall. I can stuff my foot into it, and it will get past that bog and jump forward. I can feather the pedal and make a series of mini-stalls, if I try to hold the pedal in just the exact stall position. This occurs at any speed. Take foot off pedal, the depress it just a bit past slightly, and I get a 'cough'- like a quick buck. It doesn't repeat it, unless I let off the accelerator again, and move it past that sensitive position. If the car is under load, like, I'm headed uphill, at a stop, or if the air is on, then, I MUST press the pedal past this problem position smartly, or else the bog kicks hard enough to stall the engine., from idling.
Now, this only happens when the pedal is pushed down, never when it is released. But what triggers the quick buck, or stall, is the position of the accelerator. I've checked the vacuum, replaced the wires and plugs, cleaned out any carbon build up. I had a scope hooked up, and it threw a code from memory, just said,'stall detected', but no more detail.

If this doesn't change your thoughts about the temp sensor, I'll go right out and change it. Because it seems to be related to the temp, it makes sense, but I wanted to give more specific data, in case this is some oddity you've seen before.

It appears as though you may have a bad throttle position sensor. If it is bucking like that though I'm surprised the SES light isn't on.

[xdanx25]

turns out the people we got it from did the timing chain and apparently didnt put it back on right so thats what the problem was. thanks for your help though