2002 Mazda MPV

Engine Performance problem
2002 Mazda MPV 6 cyl Front Wheel Drive Automatic 73000 miles

i have been working in my wifes car, found huge vacuum leak, fixed it ( crankcase vent hose melted ) and I have sprayed " throttle body cleaner everywhere looking for other leaks, none ! ) Also codes showed a bad MAF, IAC, cylinder 1 misfire. Under any load condition engine bogs, runs rough and backfires out both ends, also has a stumble at idle, I replaced the MAF, IAC, spark plugs, TPS and air filter, I have a rock solid 18" of vacuum at idle and there is no drop at high RPM in the vacuum. And on level ground the car will maintain a smooth 75mph, ( just backfires, kicks and sputters till it gets there ) no new codes, still runs scary bad ! I dont know where to go from here, egr. Fuel pressure, ecm?
( give up and give it to a auto mech ) ( I have 30 years heavy diesel repair experience ). Help
Mark youngkeit
June 21, 2009.

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