2003 xtype, owned it for a month, when sitting idle, drops to 500 RPM then shutters and lights dim, then back to 1000 rpm. It also shutters when driving at a consistant speed and trying to acelerate. Took it into a dealer ( not a jag dealer) today and they said it was because the coolant was low....... still doing it wasted 100 bucks, any thoughts?

 

ghachey, sounds like 2 separate issues. The low idle sounds like the throttlebody is sticking (computer opens the butterfly valve slightly to maintain the idle). Since the throttlebody is sticking, the RPMs will waver a bit more since the computer needs a bit more variance to get enough signal to the throttlebody to overcome the stickiness.

As for the acceleration issue, I would be looking at one of the coils (you have one on each plug). If one of those develops a crack in the top and you get a little bit of moisture inside, it can cause the coil to act up and it seems to raise its head when trying to accelerate. You can look at the top of each coil and if you see a crack in the clear coating on top, replace it. You can sometimes get a little bit of help by doing a long/hard acceleration and it will cause the affected cylinder to pop a code (normally a P030X code with the X being the cylinder that is acting up).

 

thanks alot, how do I address the throttle body issue

 

Coolant? Coolant????? Might be a bad alternator. Had this happen on my 2002 x. similar symptoms. good test: turn car on. leave it in park. turn on your dome light.
step on the brakes..... do your lights dim when you step on the brakes?

 

Heh! I was going to recommend he checks his wiper fluid, but didn't want to sound too facetious :-)

Seriously though, might be worth your while to drive it up to Advance Auto and have them do a free alternator check.

 

ghachey, to clean out the throttlebody, all you have to do is first go to the auto parts store and pick up a can of "throttlebody cleaner". No, not carb cleaner, THROTTLEBODY CLEANER. Then, when the motor is still warm (doesn't have to be right after being driven, but the warmer the engine the better), pull the intake tube off of the throttle body and then using a screw driver or a wooden stick, open the flapper inside the throttlebody and if it looks tan/golden, squirt it with the throttlebody cleaner. Make sure to catch the edge of the flapper too (should see a nice dark brown layer there). Once you get it all sprayed out, reinstall the intake tube. From there, start the car. It will be hard to start because you have essentially just flooded the car. But, it will start. Get it started and let idle for a minute or two. On a side note, you may also get the CEL. This is normal, so, don't worry. After a few starts of the car over the next day or two, the light will go out (takes 5 starts and on the 6th, it will clear).