Although it is running smoother with the freshly scrubbed throttle body and new IAC, it's still misfiring when cruising at low throttle on the freeway, and the fuel trims haven't changed.

I pulled the EGR valve off. I've got vacuum on one port and exhaust pressure on the other. I installed a used EGR (cleaned) from the junkyard but no change. I then left the new one on the engine but hooked the electrical connector to my old EGR to see what is was doing. The pintle doesn't move. I tried it in every gear (with the parking brake on) and at idle, rev'ing it, or low constant throttle the pintle does not move.

Does having the parking brake on prevent the EGR from functioning?
Under what conditions does the EGR open?

 

I' m having similar issues. I bought a cen-tech obd 2 reader and I have no codes but a couple of (?) marks for a few things. I replaced the plugs, wires cap, rotor this weekend. I now have a O2B2S3(V) when I tested the o2 sensors. The scanner book doesn't tell me more than that. I'm assuming it's bank 2 sensor 3. where the heck is it at? like a dumb a** I changed the only sensor I saw on the drivers side in the mnanifold. At $48 a pop need to get the right one! My whole reason for this is a rough idle and that the original owner never changed anything with 128,000 miles.

 

It was leaky injectors. Problem solved.