I have the 2004.5 EC and when I am running at sloow speeds ( 5mph ) I get this lurching where it speeds up and slows down. :eek:

its surging and there was a PCM update to address that. I think it was PIP3129.. try a search on that, its here some where.

I have it on my computer..here ya go..

04 6.6 LLY Smoke , Fuel Knock , Surging and High Injector Balance Rates - kw white black idle surge rough noise accelerate P0300 P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308 miss misfire SES DTC #PIP3129 - (Sep 10, 2004)
04 6.6 LLY Smoke, Fuel Knock, Surging, and High Injector Balance Rates
The following diagnosis might be helpful if the vehicle exhibits the symptom described in the PI.
Condition/Concern:
Customer concern may be a low speed surge (8 to 10 mph or near 1000 RPM), acceleration fuel knock noise at 1500 to 1800 RPM, rough idle, white smoke at idle, or high positive injector balance rates.
Recommendation/Instructions:
1. High positive injector balance rates (over +4.0 in park or +6.0 in drive) may be causing white smoke at idle or while driving.
2. Document all injector cylinder balance rates at the beginning of the diagnosis.
3. There is an updated calibration to address the white smoke, high positive balance rates, idle surge, and a fuel knock noise at or near 1500 to 1800 RPM.
4. Install the updated calibration and evaluate the smoking, high injector balance rates, idle surge, and fuel knock noises.
5. If there is still a mechanical concern with an injector, and balance rates are still over the SI specification of +4.0 in park or +6.0 in drive, replace only the effected injector.
NOTE: Before any injector replacements a large fuel sample should be taken from the fuel filter and checked for contaminants or poor quality.