Idle speed goes up and down sometimes stalling.

[03BamaX5]

Sure enough I just got back from a trip in the ol' x5 money pit and there is now a new problem.

Car info: 2003 X5 4.4i 103,000 miles.

When sitting at idle the idle RPM will go from 500 -700 to near stall to 1000 then back down. It repeats this 5 or 6 times every 30 seconds or so.

Wildcard: Turn the AC off and it will not do this sitting in park. But the idle still seems to be low.

If your driving and come to a stop the engine RPM will fall and sometimes will stall out regardless if you have the AC on or not.

It's like the engine can't maintain a idle under load or when the load is off. If I keep my foot on the gas a little I can keep it from stalling.

It's my understanding the 4.4i V8 does not have a IACV or the intake adjuster deal that has the valve that breaks. So that throws the two easy checks out the window.

My thoughts now are:

Something in the throttle like TPS?
MAF?
Vacuum leak?
Cam Sensor?


A 2nd problem that developed is from idle taking off I get a stuttering/hesitation that feels like a bad plug or coil pack. I replaced the plugs around 2000 miles ago and the coil packs (all 8) are new with less than 600 miles on them.

If you give it some gas it will get out of it and move on but if your driving normal it will do it bad right at take off and between the 1-2, 2-3 upshift. Once your driving at a good speed and you can see the torque converter lockup (small RPM drop) and lean in to the gas a little you can feel it too.

Can bad coil packs burn up new plugs? Replace them again since the coils are new?

Clogged fuel filter?