I'm looking for a good shop in the Denver Metro area for diagnosis of a problem? I have taken the Explorer to Lakewood Fordland, Barbee's Freeway Ford, L&R Automotive (Ford specialists in Arvada) and also AutoFX (Arvada), which not one of these shops were able to diagnose the problem I am having.

1999 Explorer 5.0 AWD w/AT @ 59K miles

I'll try to explain the problem as quick as possible:
Started up the X in July and noticed the engine was running rough, and I could feel a pulse through the brake pedal when applied. About 1 block later the CEL came on, and was diagnosed to be a bad #4 plug. Had all 8 plugs & wires changed out with Motorcraft plugs & wires, and CEL has not come back on. Since that point I've had an intermittent problem I'd describe as: lack of power, loss of power, and rough idle. This problem is most noticable when: driving on any form of incline, between 30-40mph (OD off) or between 40-50mph (OD on), trying to pick up interstate/highway speed, when reaccelerating from slowing down or coasting. I've replaced the: EGR, TPS, IAC, PCV, all 4 O2's, Fuel Filter, Fuel Pressure Regulator, plugs and wires which nothing has helped. The idle runs at about 1200 RPMs when started cold, until it warms up. Which I think is high even when cold, since it never idled this high before the problem. The X doesn't have the push you back in your seat power upon acceleration anymore, this would be the loss of power. Lack of power is when the problem is at it's worst during the above scenerio's. When the speedometer is 30-40mph(od off) or 40-50 (OD on), the RPMs are right around 1500. When the X is around this point, the X stubles every once in a while and the engine sounds like it's bogging down. Also when accelerating sometimes, the RPMs will drop 300-400 instead of climbing. It doesn't drop because it shifts, the RPM's just drop and I feel the power loss through the gas pedal. The Engine tone doesn't sound right, and the exhaust tone is deeper now.

One of the above shops stated the problem was the IAC & fuel pressure regulator. Neither of these items worked. The other three shops stated the X was running at spec. and they couldn't find anything abnormal or off. Please let me know of any thoughts regarding the problem, or of a good shop to check the X out. I'm getting frustrated since I've paid $400 in diagnosis fees and just over $500 in parts, and the X still runs like doo. Thanks for the help in advance everyone!