Expy engine shudder??

[Guest]

A couple days ago while waiting in our 2000 X outside our kids' school I noticed (while sitting idle in park) it has a noticeable shudder to it . We've had it for 3 years and I can't remember it being as bad as it is now. It almost seems like it wants to stall out. Its not intense shuddering to were it shakes the vehicle violently, its very subtle yet worse then I can remember it ever being. I sat and watched the RPMS to make sure that they sat in one place when in park and werent fluttering up and down. I watched carefully and they seemed to sit sationary in one place. Does anyone have any ideas what the shuddering could be caused from?

 

[PaulC]

Bad coil pack(s)?
Bad engine or transmission mounts?
What RPM is tach reading at idle? Too low could indicate a bad Idle Air Control valve.
How many miles on Expy?

 

[Guest]

just hit 70,000 miles .... a its now idleing at just about 1 rpm .... bout 1.2 - 1.3

 

[PaulC]

You should be idling at about 700 RPM. Idle speed is usually tightly regulated by the Idle Air Control valve and the Throttle Position Sensor. I also have to wonder about a vacuum leak affecting idle speed and quality. Notice a recent decrease in fuel economy?

As you are obviously aware, something is amiss.

Hard to diagnose over the modem. A trip to the dealer may be in store.

 

[bnvus]

Is the A/C on? Sounds like the compressor cycling. Could be on its last leg. Might want them to check it out.

 

[Guest]

I've also experienced same symtoms (01 X). Have you experienced sudden rev at idol which causes vehicle to move forward? Any thought on sudden rev?