[madmaxx]

Mine cruises all day at 1400 rpm as smooth as a rolex watch. You need the correct carb, it is a knonw issue with early Roush engines. You need to find the right person at roush to talk too.

Originally Posted by GEE TEE

My engine is #180, built in 2005, it now has 13,500 miles. Since I'm the third owner of the car/engine I doubt Roush will help me out with the performance issues. In fact, I've contacted them twice asking for carb tuning specs (jets, power valves, diaphram springs) so I could verify my carb is as it came from Roush. So far, no response. There are lots of things I'd like to know about this engine (recommended plugs/gaps, timing, advance curve) but Roush is keeping quiet. I have eliminated my tip-in stumble through a coordinated attack on initial timing, advance curve, idle speed, idle mixture, and diaphram spring change. The jets and power valves should be OK based on the AFR plot on a recent dyno sheet I received with the car. The car is much more driveable now although it still won't idle below 1100RPM, and it bucks and complains if I ask it to cruise below 1800RPM. Maybe I'm just asking too much from an engine with a big (how big is Roush proprietary info) cam.