Q&A

It could be many things, unfortunately and without experiencing the problem first hand or being able to do some basic diagnostic tests its hard to say. Start with the basics, is the engine intake vacuum approximately 21 in HG at idle, if escaping exhaust gas wont harm anything maybe remove an oxygen sensor to see if giving exhaust gas a place to "escape" makes the engine accelerate better then perhaps the exhaust is restricted. Did you replace the fuel filter on the chassis rail? Check fuel pressure should be about 62 psi, try cleaning the mass air flow meter but only use a product CRC product # 05110 .
A professional grade scan tool may be needed to monitor and read live sensor data to get to the route of the problem.
There is a company that independent auto repair shops get their information from, this same information is available inexpensively for people that work on their own cars.. The information is year make and model specific, covering repair procedures, torque specifications, fluid capacities and specifications, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate http://bit.ly/AllData_Repair_Manuals_Online