*bogs(hesitates) 2k-3.5k Rpm: Need Help!!!*

[jonsonton]

Hi,

I'm new here, but here it goes. I have an '87 Z28, 305 4BBL(VIN H), 4Sd OD.

My problem is at idle, both in park and drive, it will run fine, no apparent miss and or hesitation. With slight throttle leverage it will accel just fine, but when I punch it(3/4-full pedal), it will chug and hesitate. No codes are present, good fuel pressure(about 10psi), and I recently did a full tune-up(plugs, wires, oil change, air filter, fuel filter).

Any help would be appreciated. Thanks

[jonsonton]

I hate to answer my own question, but here it goes. I've been reading various manuals and they state that EGR valves begin to open at around 1800RPM. When the computer reaches this RPM, the engine is in closed loop, and is at normal opertating temp, it will open the EGR, via an internal or external solenoid, or intake vacuum(depending upon the type of EGR). This cuts fresh airflow slightly to allow for the increase of exhaust gas entering the cylinders.

This is where I think my problem lies. Either my EGR valve is stuck closed, or an intake port is clogged, restricting the flow of exhaust gases.

If this sounds right please reply.