Help!! Rough idle and/or miss

[murrajm5]

I have had my 94 explorer to the dealer 4 times and have replaced plugs, wires, air filter, fuel filter, had the throttle position sensor checked, checked and cleaned the MAF and the idle air control valve. I just purchased the code scanner from WalMart and code 111 during KOEO but code 33(not closing properly) during KOER. I had replaced this Oct. '98 and was wondering if it is normal for these to go bad so quickly and if it could be the source of my idle problem. I have read a lot of posts about the fuel pressure regulator but a mechanic at the dealer let me borrow their's and I checked it at idle and while pushing the throttle and it read 30 psi at idle and while punching the accelerator it jumped up to 40-45 but right back down to 30. I didn't check with the vacuum hose of because I didn't know to do so (I didn't have my Haynes manual with me). Anyone have any other ideas or ways to check what is wrong? I may end up taking to another dealer to replace parts that aren't broke.